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The Fishroom Library Archives —
Articles on Foods (live and otherwise) and Feeding Killifish (1996-2000)
An archived collection of articles, tips, and information about tropical fishkeeping in general, and killi-keeping in particular, from past issues of the G.C.K.A. Newsletter. To read an article, please click on the title (in blue).
All material is copyright © G.C.K.A. or the authors, unless otherwise noted. Reproduction is permitted for non-commercial purposes only (i.e., club bulletins). We do request that you provide source credit, and send us a copy of the publication in which the article appears. Please forward to G.C.K.A., c/o Recktenwalt, 4337 Ridgepath Drive, Dayton, OH 45424.
More than you ever wanted to know – about Blackworms
Bloodworms … a cautionary note – some may have allergies to this killi food.
A few views on hatching out Brine Shrimp
Another Method for Brine Shrimp – one breeder’s method for hatching nauplii.
Brine Shrimp Nauplii– diminishing supplies of eggs, rising prices.
Brine Shrimp as a Major Food Source – one killikeeper’s technique.
Raising Adult Brine Shrimp
Can you Overwinter Daphnia? Of course!
Cheap Killie Food – by George Davis. Alternate sources for fishfood.
Collecting Live Foods – an overview of what you can find in your own backyard.
Confused Flour Beetles
Culturing Greenwater
Daphnia – an overview of this always useful live food.Decapsulating Brine Shrimp Eggs (1) – a few methods shared.
Decapsulating Brine Shrimp Eggs (2) – more tips and techniques.
An Easy Live Food – Microworms – one of the simplest live foods for your small fish.
Feeding Our Fish – some basics about this important aspect of fishkeeping.
Feeding Killifish … A Few Useful Recipes
Feeding Killies – Dry Food for Killifish
Foods for Small Fry – A review of some of the alternatives to baby brine shrimp.
Foods for Fry – Cyclop-eeze
Fruit Flies – Drosophila melanogaster
How I Do It – Baby Brine Shrimp – One aquarist’s technique.
How I Do It – Whiteworms – Tips from Al Anderson.
Live Foods – Moths
Nutritive Additions … Spirulina
Paste Foods – Another Alternative – Two proven recipes.
Puttin’ Live Food By – a few ways to preserve some of that summer bounty.
Red/Black/Tubifex Worms – a Safe Food for Killies?
Vinegar Eels – culturing this easy live food.
White Worms the Easy Way – by Tom Cook. An alternate, non-soil method of culturing white worms.
You, Too, Can Feed Live Foods – some of the live foods that are as close as your own back yard.
Yumm … Mosquitoes – they may be a bother when they bite, but killifish love ’em!
More than you ever wanted to know about … Blackworms
Tubifex worms have long been known in the killifish hobby as an “egg-building” food, but they have a downside: they often carry a number of fish pathogens, resulting in unexpected outbreaks of disease in breeders’ tanks.
The Carolina Blackworm, an aquatic relative of the earthworm, is a clean and easily handled alternative to tubifex. Hardy, nutritious and inexpensive, they come from clean water sources, and carry no potential pathogens.
Under the proper conditions, blackworms can be kept for significant periods of time without trouble, and may even increase their numbers by segmentation and growth of the fragments. Storage for blackworms is fairly straightforward: use shallow refrigerated trays. Keep the worms wet, just covered in water. You can add a layer of wet newspaper or paper towels if you like. Once daily, rinse the worms twice. If you cover the storage tray, be sure it is not airtight.
Feeding blackworms to your fish can be a challenge, since they swim freely. Once in the aquarium, they will live indefinitely, actively scavenging on debris and hiding where fish often cannot reach them. Try using a shallow glass dessert dish to give the fish a better chance at them. “After the second rinsing,” says Charlie Nunziata, “I pick up the worms with a turkey baster… then slowly insert the baster into the aquarium to just above the dessert cup.” Gently squeezing the bulb of the baster pushes out a quantity of worms, which sink into the container. Larger fish may throw worms out of the container while feeding, and some worms will usually manage to escape. Just retrieve them with the turkey baster.
Almost all killies will feed heavily on blackworms, but young Nothos and Fundulopanchax may occasionally overeat to excess, resulting in loss of the fish. As good as they are as killifish food, blackworms are a bit large for some species, and may need to be chopped up for feeding.
One caveat: Blackworms are extremely sensitive to salt. If you use salt in your tanks, watch blackworms carefully when feeding, to prevent a mass die-off that will foul the tank.
Reference: Nunziata, Charlie. “Blackworms: A Great Food,” Suncoast Killifish Society Newsletter, Volume 5, Issue 2.
— G.C.K.A. Newsletter, June 2005 Return to top of page
Bloodworms …a cautionary note
By Donna M. Recktenwalt
In recent months (mid-summer 2000), the killifish e-mail lists have contained a number of discussions about the pros and cons of feeding bloodworms to killifish.
There is little debate that bloodworms are a good food for killifish, being eagerly taken and providing a high rate of nutrition. But food value aside, bloodworms may pose a hazard to killikeepers, particularly those who tend to have allergy problems. Based on the limited input of those participating in the e-mail discussion, allergic reactions to bloodworms are not that uncommon, and seem to take two primary forms – a contact dermatitis and a respiratory response.
The contact form, usually resulting from handling the frozen product, can result in itching, swelling, cracking and peeling and/or blistering of the skin of the hands or swelling of the fingers.
“I have an allergic reaction to frozen bloodworms,” says Joe Ponnath. “My hands break out in tiny blisters and itch horribly. My reaction to freeze dried bloodworms is completely different. I have fits of uncontrollable sneezing. … The dust gets in my eyes and causes conjunctivitis.” Another killiekeeper reports that his fingers swell when he handles the frozen bloodworm product.
The respiratory response can be immediate or delayed by some number of hours, and usually involves some combination of runny nose, watery eyes, and sneezing, and varying degrees of respiratory difficulty. The reaction may merely be a mild nuisance to many, but in some people can cause acute respiratory distress or asthma leading to hospitalization.
“I don’t use [freeze-dried bloodworms] anymore because I’ve developed an allergic reaction,” says Bill Vannerson. “This happened after about two years of use. The first time I got a reaction I thought I was just suffering from a cold. … I woke up all wheezy and clogged up. …The next time I used them during the day. The reaction was unmistakable, and strong. It scared me.
“If you are not allergic to them,” he continues, “bloodworms are an easy food source for killies, which they readily accept. But if you ever develop symptoms or believe you may be developing systems, get rid of them. There are too many alternatives available” to afford taking the risk.
“I also developed a major respiratory allergy to freeze dried bloodworms,” says Joe Bulterman. “It took a while to develop as I had been using them for quite some time.” The symptoms are quite severe with a delayed onset and a sustained acute phase (4 hours).
Bruce Turner offered a possible explanation for the allergic reactions.”The allergen in the bloodworms is probably the red hemoglobin-like protein that gives them their characteristic color,” he says. This protein, erythrocruorin, is also found in many other invertebrates, including annelid worms and molluscs. “If I had such an allergy,” Bruce suggests, “I’d stay away from worms too.”
A bloodworm (a larval midge of the genus Chrionomus) “is little more than a slightly impure preparation of erythro– cruorin – it’s there in gigantic amounts,” he continues. Why erythrocruorin should provoke such a response no one seems to know.
“One suggestion for people who have a sensitivity but still want to use bloodworms,” suggests George Trumbull, is to “use frozen bloodworms (the kind that come in individual portions), pop them out into some (clean or tank) water, swish them around a bit and add the bloodworms with the water to the tank. I’ve done this for years and it has had no adverse effect on water quality.” The trick also works well with frozen brine shrimp.
For handling freeze-dried bloodworms, Joe Gardner suggests this technique. Soak the freeze dried bloodworms in water to get rid of the dust, then use a turkey baster and a small clear container that hangs on the side of the tank.
“What I do now when feeding freeze-dried bloodworms,” says Joe Ponnath, “is hold my breath, squint my eyes, and feed the bloodworms very quickly. I then immediately … [leave the fishroom,] wash my hands, and wait 15 minutes before going back to my tanks.”
“Make sure you pay attention to your breathing while you feed so you can detect any early symptoms,” warns Bill Vannerson. Wear rubber or latex gloves, or even a surgical mask. “Allergens develop through contact over time. Any barrier you can place between the body” and the allergen will slow down any potential reaction.
In short, if you have any hint that you’re developing a sensitivity to bloodworms, handle them with great care, minimize any required physical contact, and be alert to developing symptoms and problems. Hopefully, few of us will have to deal with such allergies, but for those who do, some careful precautions may go a long way to reducing (or preventing) a problem.
Reference: Reichenback-Klinke, H-H, and Baur, X. “Allergic reactions after contact with dried fish food (Chironomids).” Aspects of Human Health in Connection with Fish and Fish Food. Contributions to Bish Biology, Gesundheitsprobleme des menschen im zusammenhang mit fischen. Beitrage zur fischereibiologie, 1982, pp. 9-17. Fisch Umwelt/Fish Envirion., no. 11. A report is given about allergic reactions in man after contact or breathing of the dust of freeze-dried fish food. As responsible agent the blood component hemoglobin of chironomids (erythrocruorin) was detected.
— G.C.K.A. Newsletter, August-September 2000 Return to top of page
A few views on hatching out Brine Shrimp
By Donna M. Recktenwalt
Most killikeepers are aware that one of the best foods for fry is baby brine shrimp (nauplii). But having a fresh supply requires that the aquarist hatch his own, and there is often lively discussion on the best way to do this.
“Metabolism of the brine shrimp embryo begins when about 60% of the cyst is hydrated,” reports Dr. Patrick Sorgeloos, of the Artemia Center, Ghent, Belgium, “provided the cysts are sufficiently illuminated. At too low light intensities the hatching rate is delayed or the cysts will go into a ‘reversible phase,’ and not hatch.”
Strong illumination at the start of incubation is necessary to trigger the hatching mechanism. 24-hour illumination will ensure enough light. Minimum light requirements for hatching vary somewhat, since different strains of Artemia have different composition and thickness of the corion (outer layer of the cyst).
For decapsulated cysts, less light is needed because the outer corion is chemically removed. Decapsulated cysts will hatch with only about 1/4 the light levels required by whole eggs.
Although light is important, the actual hatching is more the result of water and oxygen entering the cyst. As salinity levels increase, hatching is delayed. “We recommend using no more than one tablespoon per quart of water for hatching out cysts,” says David Kawahigashi. Decapsulation will help the hatch rate by about 10%, due to the reduced energy required for “breaking.”
“If properly hatched – pH >8.0, Salt=98 grams/ gallon (3.825 liters), temperature about 22°C (72°F), water hardness of about 50 ppm (as calcium carbonate), and a good bit of aeration, brine shrimp eggs usually hatch in about 36 hours,” says Bob Schwiegerath. “Start another hatch (religiously) daily.” If your water has a pH much lower than 8.0, he suggests using baking powder (sodium carbonate) to bring the pH up.
The “traditional” hatching method for brine shrimp involves a hatching cone or inverted pop bottle with the bottom cut out, and vigorous aeration. “I use … four inverted pop bottles and cycle them through,” says Richard Sexton. “One has fresh eggs, one is a day behind and has a few nauplii, one is two days behind and has a full crop, and the next one has a waning crop and would have eggs added the next day.”
Others have used other methods with success. “Don’t use hatching cones,” says Harry Kuhman. “Don’t even bother with soda bottles any more. Hatch brine shrimp in trays (plastic shoe boxes, actually) with dividers in them, no aeration… Shrimp swim under the divider towards the light (the larger hatching compartment is painted black), and collect there. I seem to get better hatch rates this way than with aeration. You can [also] keep adding eggs and removing baby brine shrimp for several days until the water level gets low enough to start a new batch…. I get a good hatch in about 24 hours.”
Brine shrimp require salt water for hatching. Although most aquarists use aquarium salt for this purpose, there are other possibilities, including waste seawater from a saltwater tank, used full strength. Using gallon jars for incubation, with bright light and vigorous aeration, the nauplii can be harvested at 48 hours. Juveniles and adult brine shrimp can also be grown in this waste seawater, using large flat containers with lots of overhead light.
When hatching eggs in full strength seawater, filter through a brine shrimp net, then place the nauplii in cold tap water; the live nauplii sink and the shells float. Lots of brown (unhatched) eggs on the bottom after 15 minutes means either the eggs or the water were no good.
“I [have] tried seawater,” says Wright Huntley. “It worked almost exactly as well as the somewhat weak ‘Instant Ocean’ mix I had been using, but I could see no real advantage. Both were better than rock salt, and probably better than salt plus baking soda (to raise the pH).”
“I’ve been using ocean water,” says Oleg Kiselev. “It lasts forever without fouling. I can hatch brine shrimp in the same water for months without the water picking up the disgusting ‘dead shrimp’ smell, and it gives me tremendous hatch ratios.”
– G.C.K.A. Newsletter, November 2000 Return to top of page
Another Method for Brine Shrimp
“Everybody but me uses an inverted pop bottle,” says Lee Harper about his brine hatching setup. “I use right side up 2 liter plastic bottles with the top cut off” just above where the neck flares out. Don’t throw the top away–this cut off piece makes a useful funnel.
“If the [brine shrimp] eggs are good and the aeration is adequate, the rounded bottom is just as effective as the cone shape.” The advantage is that no hanger or rack is required to hold the hatching bottles. Lee sets them inside a styrofoam box with a 15 watt light bulb above them for light and warmth, then siphons out the shrimp from the lower middle area after they have settled. — G.C.K.A. Newsletter, September 1999 Return to top of page
Want to Raise Those Naupli?
Raising Adult Brine Shrimp
Brine shrimp have long been a staple of aquarists, in both their nauplii and adult forms. Brine shrimp can provide a reasonable source of both carotenoids and hemoglobin in the diet, but should not be used as a sole food source.
For some aquarists, collecting live brine shrimp from the wild is possible. Most of us must buy or raise our own. Hatching out brine shrimp cysts is easy; raising them to adulthood may be quite difficult, requiring volumes of water, gentle currents, sunlight, and time.
“About 10 years ago … I raised brine shrimp on a regular basis,” reports Brian Watters, “but more for my own amusement than as a source of live food. Even when successful, the number of brine shrimp one can raise is not worth the effort.” Brian worked with several container sizes, the largest being 10 gallons. He used marine salt to reach a specific gravity of 1.040 (about twice seawater). A small sponge filter provided moderate circulation. He inoculated the setup with newly-hatched nauplii and fed yeast (just enough to turn the water cloudy), growing the shrimp to adult size in 2-3 weeks. Later on, Barry tried various other foods, with varying results. “The bottom line,” he says, “is that it is an interesting experience to raise brine shrimp.”
Some time back, an article in Aquarium Fish Magazine suggested using a series of 2-3 liter pop bottles, cut and mounted as you would for a brine shrimp hatchery. Newly hatched nauplii were added and the bottles set in a sunny window. After the nauplii had reached 1/8″, green algae from the bottom glass of an aquarium cover was blended with water to feed them. “Many aquarists kill brine shrimp with kindness by overfeeding them,” the article continued. “Neglect them and you are more likely to get a brine shrimp culture established.”
An internet source (Artemia FAQ 2.0, available at http://www.aqualink.com/marine/z-atemia.html), suggests using a 10-20 gal glass tank with acrylic panels set into the corners to make an oval. Add to this a series (6-8) of lift tubes to provide a constant circular water flow. Best growth rates are achieved at 25-30° C (77-86° F) with salinities of 30-50 ppt and low light levels. Recommended foods were microalgae and inert foods such as yeasts, rice bran, whey, etc.
Andrea Caiola, from Italy, reports some success using 6.6 gal. glass containers filled with very hard tap and distilled water in a 50/50 mix. He added non-iodized salt to reach a density of 1035, placed the container outdoors where it was exposed to sunlight for part of the day, and left the water to age. After more than a month (the water had turned quite green) he introduced some nauplii and waited. In another couple of weeks he began to feed them, using a blend of wheat flour (85 g.), brewer’s yeast (10 g), and spirulina powder (5 g). He fed a small amount daily, being careful to not overfeed. “I have seen a friend’s tank filled with more than a hundred adults raised this way,” he reports.
The bottom line? For feeding your fish adult brine shrimp, it may be less expensive to simply purchase them from wholesale suppliers.
— G.C.K.A. Newsletter, February 2003 Return to top of page
Dedicated fish breeders have long known that the newly hatched nauplii (larvae) of Artemia salina (brine shrimp) are a perfect food for small and newly hatched fish, providing essential proteins, fatty acids, carbohydrates and carotenoids in an easily eaten, moving prey package.
Brine shrimp eggs are easy to hatch; the nauplii are simple to feed. Although hatching devices take many forms, all utilize nothing more than salt, water, and an airstone. The results have proven worth the effort in healthier, faster growing fish.
However, brine shrimp eggs are subject to the economic law of supply and demand.
Due to a worldwide boom in commercial aquaculture and several years of poor harvests, prices have risen sharply. Most (but not all) brine shrimp eggs are harvested from Utah’s Great Salt Lake, where more than 13,000,000 pounds were harvested in 1991. In 1996, the take was less than half that. Part of the drop was due to changing conditions in the lake, which resulted in the birth of live young by the shrimp, rather than deposition of cysts (eggs), but part of the decline may also have been due to overfishing: the number of licensed boats numbered less than a dozen in the early 1990s; by 1996 the number had topped 60.
The result has been a rapidly escalating price spiral. Fortunately, when stored properly in a cool, dry, dark place, brine shrimp eggs will last for years, and although commercial hatcheries may need to pay close attention to the guaranteed hatching rates, this is less of a factor for the hobbyist. So if you find a supply of brine shrimp eggs at a reasonable price, you might want to stock up.
Reference: Davis, Chuck. “Brine Shrimp,” Aquarium Fish Magazine, April 1998.
— G.C.K.A. Newsletter, Sept/Oct 1998 Return to top of page
Foods …
Brine Shrimp as a Major Food Source
By Donna M. Recktenwalt
“Brine shrimp eggs/artemia cysts have been the life source for my killies for nearly 25 years,” reports Dave Koran. “My cost in feeding mainly newly hatched brine shrimp, supplemented weekly with daphnia and occasionally with white worms and microworms, is not much more than 50 cents per day, and I’m feeding maybe 200 containers with fish each day.”
Going through that much “shrimp” and depending on it as a main (and sometimes only) food for his fish, Dave’s supply must be dependable. The keys to dependability are:
1) the eggs,
2) a dependable source of air,
3) sufficient eggs in various stages of hatching, and
4) a rigorous routine for preparing the shrimp for feeding.
Each day he sets up from 1 to 3 gallon-sized jars with approximately 1/8 cup of eggs/cysts per jar. When he prepares a gallon hatching jar, he cleans it, adds water and 1/4 cup of salt, and then places an air tube in the jar, letting the salt dissolve and the solution come to room temperature for a day before adding the cysts. The air supply must be sufficient to keep the entire contents of the jar in motion.
Hatching is a function of temperature: the cooler the hatch water, the slower the hatching process. In Dave’s case he keeps the hatching jars on his basement floor at 60-72°F; under those conditions, it takes 2 to 3-1/2 days for a hatch, which means that he must keep 4-8 jars in process all the time.
There is usually a 24-hour “window” for prime harvest. After that, quality deteriorates rapidly. To harvest the shrimp, he drains the entire jar through a fine mesh net and rinses the contents multiple times. He then returns them to a container with fresh water and allows the contents to separate: empty cysts float to the top, nauplii and unhatched cysts settle to the bottom. These he drains off for feeding to his fry. He tries to rinse as much salt from the shrimp as possible to avoid introducing too much salt into his fish containers. If you want to keep the “cleaned” shrimp for more than a day, return them to a new soluion with double the strength of salt.
Some years ago Dave “discovered” a feed grade of salt at his area agricultural/farm supply store, which he now uses for hatching brine shrimp. It is a crystalline, evaporite material intended for mix into animal feeds, and is not intended for human consumption, so contains trace elements and probably sufficient carbonate for buffering purposes.
A Few Words About Shrimp Eggs
A number of suppliers are now trying to supplement their brine shrimp egg sources with “Asian” artemia cysts, which come from the salt pans of central Asia. Russian cysts are also being used. The domestic supply is directly dependent on the health of the Great Salt Lake, and on the Utah Division of Natural Resources regulated harvest.
For the last few years Sanders (of Ogden, Utah) has sold short shelf life eggs, which means that they don’t last long once opened. If you can get them, the short life eggs will often run 1/3 to 1/4 the price of equivalent grade regular eggs. Occasionally, however, you’ll get a bad can of eggs. Usually Grade A eggs are pretty consistent in hatching, with B and C grade eggs having more duds (on a per can basis). If you decapsulate your eggs for feeding, purchasing the B or C grade eggs may be a way to save you money, since the decapsulated cysts are nutritious for fish food even if the embryo does not hatch.
– G.C.K.A. Newsletter, January 2000 Return to top of page
Tired of spending megabucks per pound for fish food? Then read on …
Cheap Killie Food
By George Davis
Tired of spending megabucks per pound for fish food?
The way I figure it, if it’s good enough for the U.S. Government, it’s good enough for my fish. If I can eat it, it has to be OK for them, and there’s no chance of bringing in the problems from Tubifex or other live foods.
Clams – Minced clams at the grocery store sell for about $4 a pound. Run them through the food processor, then freeze them. When you want to feed, slice with a razor blade and feed the flakes. For some reason my rainbows don’t seem to relish it, but most others do.
Mussels – $1 to $2 per pound live. Stick the whole mussels in the freezer. take them out one by one, open with a screwdriver and slice with a razor blade. My killies haven’t complained yet. You probably could harvest all the meat, dice and freeze, but I haven’t tried that method yet.
Squid – $2 a pound at the fresh seafood shop. Skin the squid, pull out the beak and cartilage, and chop finely with a sharp knife. Freeze, then shave off small pieces. Don’t run it through a blender, as it makes a muddy mess.
Soft Shell Crab – Left over fish bait? Those soft shelled crabs make excellent fish food, and one of the most enjoyed by my fish. My reef tank enjoys left over minnows, but I’m out of those and haven’t had the opportunity to try them ground up for killies.
Earthworms – I haven’t tried this myself yet. Collect the earthworms from a clean, organic garden area, wash off the dirt, freeze, and slice with a razor blade. Your fish will love them. I have heard that you can purge the worms of dirt with cornmeal, although I haven’t tried it.
Blue Crabs – Some crab get a little too old for you to enjoy it? Even cooked, the fish seem to love it. For other foods, I would definitely recommend raw.
Others may disagree with me on the above, but my fish are happy and I’m not spending $25-$50 a pound for fish food. I feed this stuff to my Africans, mollies, catfish, whatever. I wouldn’t suggest it for any of the vegetarian fishes.
— G.C.K.A. Newsletter, May 1997 Return to top of page
Collecting Live Foods
By Donna M. Recktenwalt
“At this time of year my fish get extra special food,” says Jim Robinson. Within two weeks after the ice melts, live food becomes plentiful.
“Fish in general, and killies specifically, do better on a large variety of live foods.” Frozen and prepared foods are excellent, but live foods are better. In some fish the egg count may triple to quadruple when live foods are a major part of the diet.
Where to find live foods? “Look in temporary or permanent ponds where water collects and stays for more than a month,” suggests Jim. Suburban sites are possible, but in many cases you will have to go beyond the city boundaries to find good live food collecting spots.
“My favorite spot,” Jim says, “is a large ditch on both sides of a country road. Water drains into this marshy area from a farm that houses horses. The runoff from the manure pile eventually disgorges into this swampy area.” From this site he collects fairy shrimp, mosquito larvae and daphnia in large quantities. Be certain to ask permission to collect from sites that are on private property, although most folks are quite willing to have you collect ‘bugs’ from their ponds.
“I went collecting …[in my favorite pond] in the middle of February,” reports Greg Niedzielski. “I wasn’t’ really sure what to expect as I had never been to the pond so early in the season. I was pleasantly surprised by large numbers of half-grown fairy shrimp…. There was still some ice on the pond, but … I had no difficulty collecting enough Fairy Shrimp and Daphnia to fill my bucket.” A couple of weeks later the pond was totally ice-free. As the season progresses the population of the pond changes.
“The pond I visit these days is under an old highway bridge,” Greg says. “There are railroad tracks running past it and a couple of small businesses nearby. The water collects between the concrete bridge supports, and early in the year when the pond is at its greatest extent it is three feet deep or so.”
The fish certainly seem to enjoy the results of such collecting trips: “they attack the food with far more vigor than they do frozen or flake food, and eat much more of it.” Daphnia and Fairy Shrimp will survive for a few days in a tank, so you can load up the fish and simply wait for them to finish it off.
“There is always the possibility of introducing less beneficial organisms into the aquarium when feeding live food,” Greg cautions. “Later in the season dragonfly larvae become more abundant, and a small, unnoticed hitchhiker can grow to become a fish-eating monster very quickly.”
And then there are the benefits to the aquarist: “there are worse ways to spend a sunny, if cool, early spring afternoon than walking through a field to get to your favorite pond,” says Greg. If your pond is in a wild enough area, you may see numerous birds, or even a deer.
As far as equipment is concerned, a few buckets with lids and a fine mesh net will do when you’re collecting live foods, although you can get considerably more fancy than that. From scientific equipment suppliers you can buy nets specifically designed for live food collecting; plankton nets are perfectly sized for easy water flow and efficient retention of any live foods you may wish to collect. Adding an old broom handle or an extendable painter’s pole to the net for extra length can be highly beneficial.
Collection itself is simple: “simply make a figure 8 motion in the water with your net and lift out your catch,” says Jim. “The figure 8 motion draws the ‘bugs’ into the net and brings them up from the bottom. Do this gently,” since you don’t want to stir up the bottom and bring excess debris to the surface. Once you’ve brought them home, keep your buckets of collected critters outside, in the shade to keep them cool, until you can either feed or process them.
What Might You Find in the Spring?
Fairy Shrimp (Eubranchipus spp.) These are found, only in the first month or so after the ice melts, in temporary pools which completely dry up at some time during the year. Their restive eggs incubate dry in the mud and hatch from months to years later. Their life cycle takes about 5 weeks and they reach only 1-1/4 inches in length. On sunny days they can be seen as red patches close to the surface of the water, making collection easy.
Mosquito larvae (Culex, Anopheles., and Aedes spp.) These can be found from early spring through summer in permanent and temporary pools. Rafts of eggs are laid on damp, low ground that will be flooded, or directly in the water. Larvae grow to 1/2 inch long, then pupate (they look like commas at this stage) before reaching adulthood. Keep these critters outside, since they metamorphose quickly, and can cause discord within the family as adults.
Daphnia (Daphnia spp.) These are perhaps the most versatile of all collected foods. They can be cultured, but that is subject for another article. Daphnia range from 1/50 to 1/5 inch in length, depending on species. Under favorable conditions, Daphnia produce only live female young; if conditions worsen, males may be produced. These then mate with the females, which then produce resting eggs (ephippia) that remain inert until conditions are favorable again.
Other Daphnia-like creatures include Moina spp., Ceriodaphnia spp, and Bosmina spp. All thrive under similar conditions and have similar life cycles.
Glassworms (Chaoborus spp.) are the larvae of flying insects known as phantom midges. These 1/4 inch larvae are found in temporary pools, and hatch from eggs that must freeze before hatching in the spring. Use caution when feeding glassworms: they are carnivorous and will eat fish eggs and young fry.
Bloodworms (Chironomus spp.) are really midge larvae, and not worms. Bloodworms can appear in tremendous quantities in the water, and their bright red color makes them conspicuous and easy to collect. The larvae can be up to 1/8 inch long, with the pupae reaching 3/8 inch. They are fairly easy to keep alive, since they thrive in oxygen poor water.
And In the Summertime?
Late spring/early summer provides other types of food than you can find in the spring. Although daphnia and mosquito larvae are still around, other things become more common. A change of technique is useful, too: bring up more of the bottom mud by moving the net faster and deeper. You’ll have to sort out more twigs and debris; you’ll also have to sort out some types of insect larvae. Feeding dragonfly larvae or hellgramites to your smaller fish simply won’t work, although some of the larger species may take them. Leaving a predacious Diving Beetle in one of your tanks can lead to disaster.
“Many new organisms appear in the summer,” says Jim Robinson. Among them are Rotifers, Cyclops, Diaptomus, Cypris, Amphipods, Isopods, Caddisfly larvae, Mayfly nymphs, Stonefly nymphs, Crane fly larvae, and Housefly larvae.
Rotifers are found all over the world, swimming in the water or crawling through the bottom mud or plants. They are very small, thus require a much smaller net mesh. For killifish, rotifers fit perfectly between the smallest infusoria and the next larger foods. Rotifers develop by means of unfertilized eggs which are distributed by the wind or by animals. Like daphnia, males only develop during deteriorating conditions, and the resulting resting eggs remain in the mud until conditions are more favorable.
Diaptomus are closely related to Cyclops and are often found with them; their major difference is their longer antennae.
Cyclops (sometimes called “water mites”) are often found with daphnia, or under the same conditions, and are most readily available from May through September. The ovoid females carrying their paired white egg cases are easily identifiable. They can be found in large masses near the surface of the water, and they can easily be cultured.
Cypris are often overlooked by collectors; they look like small black specks. These “seed shrimp” or “hard shell daphnia” resemble miniature clams and adapt well to poor water. They are a good food once the fish learn to recognize them as such. Their life cycle is similar to that of daphnia.
Amphipods, commonly called “scuds” or Gammarus, are best suited for larger killifish, due to their hard shell and their size. They will live in almost any aquatic conditions, but seem to require rotting plant material. Inspect this live food carefully: if they have small red spots, don’t use them, since the spots are the larvae of parasitic worms, which could become established in your tanks. Scuds breed almost continuously from March through November. Reproduction is sexual, and prolific.
Isopods, more commonly known as “sowbugs,” are most commonly found beneath damp wood, but there are some aquatic members of the family. Asellus is the most common, and can be collected by running your net through a patch of underwater vegetation. Young Asellus make fine killie food, but the adults are too large and hard-shelled.
Mayfly nymphs can be easily collected in deeper water by using a vigorous figure 8 motion; they have strong claws for holding on to rocks and debris. They are easily distinguished from other aquatic larvae by their three “tails.” You will likely have to do some sorting with mayfly nymphs, since you’ll probably pick up a lot of vegetation with them.
Caddisfly larvae often build cases around themselves for protection, using leaves, twigs, sticks, stones, etc. To feed them you must remove the cases: simply grasp the case at the rear and pull from the larvae. This is time consuming, but may be worth the effort.
Stonefly larvae resemble mayfly nymphs but only have two “tails.” They are usually found in fast-moving water. Collect as you would mayfly larvae. Sorting is required, and these nymphs are predatory, so feed them only to fish large enough to handle them.
Cranefly nymphs can also be found in swiftly flowing streams. Gather clumps of the bottom leaves and swish them off individually into a clean bucket. These fat bodied, soft larvae are a favorite fish food.
Housefly larvae are perhaps the simplest foods to collect and feed, if one of the more disagreeable. They can be cultured, preferably outside, using small margarine tubs and decomposing foodstuffs. They are excellent food, once the fish learn about them. Keep in mind that they can escape, so feed only a few at a time and make certain that they are eaten.
References:
Niedzielski, Greg. “A Few Words About … Pond Scum.” Killie Dirt, Newsletter of the Canadian Killifish Association, July/August
1998, Volume V, Number 4, reprinted from the March, 1998 issue of Killie News and Views, a publication of the Greater
Niagara Frontier Killifish Association.
Robinson, Jim. “Live Food Collecting: Part I – Spring Collecting,” Killie Dirt, Newsletter of the Canadian Killifish Association,
May/June 1999, Volume VI, Number 3.
Robinson, Jim. “Live Food Collecting: Part II – Summer,” Killie Dirt, Newsletter of the Canadian Killifish Association, July/August
1999, Volume VI, Number 4.
— G.C.K.A. Newsletter, April 2000 Return to top of page
Live Foods
Confused Flour Beetles
The confused flour beetle has been around a long time; remains of them have been found in Egyptian tombs and archaeological sites in the near east dating to before the time of Christ.
Especially for top feeding killifish, both the adult beetles and their larvae provide an ideal food.
Culture of confused flour beetles is simple. To a well covered container such as a gallon size plastic ice cream tub with holes punched in the lid for ventilation, add an inch or so of flour, powdered milk, or a combination of the two, and a starter of adult beetles. Put on the cover, set in an out of the way place, and ignore for a while. The cultures require little care beyond occasional freshening of the culture medium.
Although they are easy to culture, and are an ideal size for killifish food, the beetles do have a downside.
Adult beetles crawl actively; a few always seem to get loose when being harvested. Given the chance, they will infest foodstuffs. And the larvae can be difficult to separate from the food medium and their own empty pupal cases. Using a fine mesh kitchen strainer effectively separates the insects from most of the flour, but not from the shed skins; some of each always end up in your tanks, necessitating more frequent water changes.
However, some aquarists have recently found that confused flour beetles can be successfully cultured in powdered milk, either with or without the addition of a small amount of flour. To feed, simply scoop a batch of the adults and larvae from the culture medium, then rinse off using a fine mesh (brine shrimp) net. Result: clean, wet, sinkable food, with no residue to pollute your tanks.
— G.C.K.A. Newsletter, May 1998 Return to top of page
Culturing Greenwater
By Donna M. Recktenwalt
Aquarists have long known the value of greenwater.
Basically, it’s green because of the photosynthetic algae and protozoans it contains, such as Euglena. It’s an excellent food for daphnia, but it’s also food for zooplankton such as rotifers, and the larger protozoans such as paramecium, making greenwater an excellent food for fry. “The beauty of greenwater is that it is a sort of balanced ecosystem and you don’t have to worry so much about overfeeding the fry,” says Eric Lund. “In the best setups, greenwater is produced in the fry tank and no feeding is required at all until the fry get large enough to eat baby brine shrimp, at which time they can be dipped from the tank and reared in a grow-out container.”
This contradicts the generally accepted rule of “keep fry in clean water,” but has been proven to work by numerous aquarists. Benefits cited include fewer water changes, faster growth rates resulting from the constant presence of food, and the ongoing “cleanup” activities of microorganisms.
There is no doubt about the benefits of greenwater, but how do you start–and then maintain–a viable culture?
Start with Aquarium Water
“The microorganisms that make up greenwater are already in aquaria,” points out Scott Davis, so the basics are simple: well aged tank water, starter, and a source of bright light, either natural or artificial, that is available 14-24 hours a day. Within a few days to a week from the start the water will take on a greenish tinge, and microorganisms will be visible under a microscope. Eventually, given enough light and enough nutrients, the water may turn dark green and become quite opaque.
Remove any plants, which compete with the algae for the available nutrients. Keep the water moving with an airstone or a small box filter filled with stones. Add fish to eat quantities of food, stir up the water, and produce waste material. “Under optimum conditions greenwater reproduces at an incredible rate,” with 40% removal possible every few days.
There are a number of “recipes” for making greenwater. Dave Lains uses a small but effective system: one goldfish, one gallon bowl, leftover brine shrimp, and lots of light.
Or try this one from Mack Fukada: to tank water, add a crushed (or microwaved) lettuce leaf and some liquid plant nutrient, such as Miracle Grow fertilizer. (Many aquarists with plant tanks have found that fertilizers result in unusually high nitrate and phosphate levels, which result in unwanted algae blooms; for greenwater production, this situation is ideal and poses no problems to fish or snails.)
Dave Webb, too, begins with Miracle Grow fertilizer, then adds iron drops such as Sequestrene (available at garden stores) or Duplaplant 24. “If you let the iron levels drop,” he says, “the water may not stay green.”
Others, like Dale Deck, use water left over from boiling potatoes, placed near a sunny window. To feed the culture, add more potato water or cooking water from any starchy cereal grain. Alternatively, use a bit of liquid or powdered milk. These cultures are not odorless, but do produce a culture quickly.
If you feel adventuresome, you might try this recipe from Scott Page. In a blender place 2 cups of RO/DI water and one sheet of Nori (dried algae, for wrapping sushi; available in red, brown, and green). Liquify for 5 min. Filter first through window screening sized mesh, then through the finest mesh you can find. The resulting liquid will feed rotifers or baby brine shrimp. The remaining jelly can be used fresh or frozen as food for small-mouthed herbivores, daphnia, brine shrimp, etc.
– G.C.K.A. Newsletter, April 1999 Return to top of page
Live Foods
Daphnia
There are probably as many methods for culturing daphnia as there are people making the attempt. But what most agree on without question is that daphnia makes an excellent (although not exclusive) food for tropical fish, including killifish.
There are two species of these small free-swimming shelled crustaceans, Daphia pulex (fairly small and dark colored), and D. magna (larger and pale colored). Daphnia can be collected from the wild or they can be cultured, although cultures do tend to experience normal “bloom and bust” cycles. This problem can best be dealt with by having several cultures active at any one time, so when one fails another is still producing.
Daphnia have long been a staple of the aquarium hobby, and have been successfully cultured in a variety of containers, from small buckets and indoor aquaria to outdoor stock tanks, ponds, and children’s wading pools.
Proper water for daphnia culture is not a major concern; they have been raised in hard well water and in soft rainwater.
“I keep my daphnia in a 300 gallon stock tank,” says Barry Cooper. “I [first] filled it with tap water (well water, 180 ppm, pH 7.5), added some soluble fertilizer, and watched it go green. Then I added a culture of mixed Daphnia species.” The next year it filled with rainwater and had lots of dead leaves, mostly ash and maple, fairly clear, reddish brown water, and it teemed with daphnia. Resting eggs had survived over the winter and hatched when the tank filled in the spring.
Gary Sutcliff uses small plastic wading pools kept outside. He feeds the daphnia in the spring with yeast and pea flour, which gets them off to a good start. “It’s important to harvest heavily when they bloom,” he says. “In any culture you want the population to be on the growing part of the curve.” His daphnia occasionally disappear for about a month, but then came back.
Robert Nahn uses a slightly different setup. “I have three big 32 gallon plastic containers, one with green water and about 10 comets [goldfish].” The other two containers are for daphnia culture. Every few days, he collects daphnia from the culture tanks, feeds the daphnia cultures with green water fom the comet tank, and then feeds the comets with flake food. The cycle works.
Opportunistic filter feeders, daphnia have been successfully raised on green water, yeast, powdered pea soup mix, alfalfa meal, skim milk, and a variety of other foods, commercial and homemade, as well.
Charley Grimes, writing in Aquarium Fish Magazine (“Feeding Live Foods”), found that his best results with daphnia occurred when he fed mashed sweet potato baby food mixed with water, up to twice a day. “I prefer the baby sweet potatoes [because] they make the daphnia a reddish color that I like.” Neither the daphnia nor the fish they’re fed to seem to have a particular color preference. Charley’s daphnia culture tanks have an airstone for water movement and receive 50% water changes weeky. When doing water changes, use a strainer, a piece of old tee-shirt, or a fine mesh net to recover any daphnia, then return them to the tank. Eventually, you’ll have to remove the mulm buildup. Siphon it into a bucket, let it settle , then recover any daphnia you’ve missed.
Many feel that greenwater is the best food for daphnia cultures. It can be produced by keeping the containers in sunlight and feeding them with well composted cow or horse manure or fertilizer. Other foods that will help keep a daphnia culture producing include:
Powdered milk (produces a 5-15 day daphnia population curve).
Soy flour recipe. Blend together 2 tsp. soy flour, 1 multivitamin tablet, 1 spirulina vitamin tablet (from a health food store) and 6 oz. water. In a separate container put 8 oz. tank water and a pinch of yeast; allow to sit for 20 minutes. Add two teaspoons of the soy flour mix to the tank water, then feed some of this mixture to the daphnia. The rest can be stored in the refrigerator.
Vegetable juice mix. Juice together some spinach, a carrot, and a beet (optional). Feed about 1 teaspoon of the mixture at a time. Store the balance in the refrigerator, or freeze in ice cube trays; feed a cube as required.
One critical thing that daphnia need, besides a steady food source, is plenty of light. Recommendations vary, but lighting may reach 24 hours per day without harm, as long as the water temperature remains below the mid-70s (F). At higher temperatures the daphnia may go dormant. With cooler temperatures, the daphnia usually will resume active growth and reproduction.
— G.C.K.A. Newsletter, January 1998 Return to top of page
Of course, say several fishkeepers who have been raising daphnia for years.
“I had a culture of Daphnia in upstate New York, outside in a 300 gallon stock tank,” says Barry Cooper. “I rarely fed it anything, except very occasionally some yeast… They over-wintered for about 4 years before I moved to Oregon. That stock tank regularly froze solid. It had lots of dead leaves and other detritus on the bottom, which I think harbored the organisms that the daphnia fed on.” Barry also over-wintered D. magma and D. moina in Oregon, where the water froze over in his stock tanks.
Patrick Coleman reports that he when he lived in “primitive” conditions in Montana, he kept an old wooden water trough for infusoria and native daphnia. In the spring, it always seemed to bloom back to the abundance of the previous summers, despite the cold. “The addition of elk, deer and bear droppings … added occasionally, helped it even more.”
“I just [leave] the container outside,” says Al Boatman (Florida). “When it warms up after a cold snap I can see the daphnia swimming along the top of the water.”
You can siphon out the bottom debris, place it in a gallon jar or a 10 gallon tank and warm it to about 78ºF, with about 14 hours of light a day. This triggers the eggs into hatching. The addition of small amounts of organic fertilizer (in the form of animal droppings or traces of Miracle-Grow) encourage a good bloom of green water and bacteria on which the daphnia feed.
– G.C.K.A. Newsletter, December 2002 Return to top of page
Decapsulating Brine Shrimp Eggs
Those who breed fish are well aware that for fry to get off to a good start, they must be well fed. Among the many live foods that are suitable for small fry, perhaps one of the most popular are baby brine shrimp, or nauplii. These can be fairly easily hatched in the fishroom and are relished by most fry large enough to eat them. The dried eggs store well, sometimes for years. Standard hatching procedures involve salt, water, heat, and light, then harvesting of the free swimming nauplii for feeding.
In recent years, decapsulation (removal of the chorion layer) of brine shrimp eggs before feeding has become more popular. There are several advantages to this process:
1. The strong chlorine (oxidizing solution) completely sanitizes the cysts, reducing
potential introduction of bacteria or disease.
2. No separation of shells is required when feeding the naupli.
3. There is no loss of unhatched cysts; even those that do not hatch are edible, since the
thin “hatching membrane” that is left is digestible. Also, unhatched nauplii have expended
no energy stores in swimming.
4. The hatching nauplii require less energy to hatch, which can increase the hatch rate
10% over undecapsulated cysts.
The process of decapsulating brine shrimp eggs need not be a mystery. In the paragraphs that follow, two breeders share their techniques.
“I’ve been decapsulating brine shrimp eggs with good success using the following formula,” says Chris Graseck.
1. Soak 1 tsp. of brine shrimp eggs in 3 oz. of cold water for one hour to rehydrate them.
2. After they have rehydrated, add 2 oz. of bleach and stir for 3-5 minutes. The eggs will
change color, from brown to gray to gold. Remember to keep stirring; you’re done when
the mixture turns golden.
3. Pour through a brine shrimp net and gently rinse with cool water until no smell of
bleach remains.
4. In a separate container, prepare a mixture of one cup cool water and one tbs. of white
vinegar. Use a low, wide mouth jar you so can drape the net with the eggs over the top
to let the eggs soak for a minute or two. This will neutralize any leftover bleach.
5. Place the brine shrimp eggs in salt water and hatch normally. If you hatch out these the
regular way and have a lot of orange dead shrimp at the surface cut back a little on
the bleach.
Jay Exner’s technique is similar.”You will need: a small bowl (I use one of those tiny clear Pyrex bowls), bleach, brine shrimp eggs, a fine mesh net, and dechlor liquid. To the small bowl, add the brine shrimp eggs you wish to decapsulate. Pour bleach directly on the eggs. You may add some water, it doesn’t matter. Gently agitate the bowl. After a few minutes you should notice the color changing. When ready, pour the mixture into the brine shrimp net while holding it over the sink. Rinse the bowl out into the net, then gently rinse tap water through the net. Add dechlor liquid (a few teaspoons) to the empty bowl with a small amount of water, then dip the net into this for a few moments. You can pour the dechlor water through the net and gently rinse the net and eggs one more time. (It shouldn’t smell like bleach anymore). Add eggs to culture.”
— G.C.K.A. Newsletter, January 1999 Return to top of page
Decapsulating Brine Shrimp Eggs –
More Breeders Share their Techniques
More killifish keepers have started decapsulating their brine shrimp eggs before hatching. Decapsulation makes hatching easier for the nauplii by removing most or all of the chorion. In addition, fish will eat the unhatched dechorionated eggs almost as well as they will eat the live nauplii. If you have tried decapsulating brine shrimp eggs and were dissatisfied with the process or the result, you might want to try again, using one of the following techniques.
Richard Sexton
“What you will need – one pint or 16 fl. oz. of fresh water, 2 oz. of liquid chlorine bleach, 1 tbs. of white vinegar, 1 tsp. of brine shrimp eggs.
“Begin by adding 3 oz. of chilled fresh water and one teaspoon of brine shrimp cysts to a glass container. Using an air stone, gently aerate the cysts for approximately one hour at room temperature. This will fully hydrate the eggs in preparation for the decapsulation process. After one hour, pour in 2 oz. of liquid bleach. Increase the aeration or stir continuously for the next 5-10 minutes (until decapsulation is complete). The eggs will change from brown to gray to white, and finally to orange in color. When almost all of the cysts are orange, stop the reaction by pouring the solution into a fine mesh net and rinse immediately with fresh water. Continue rinsing until the smell of the chlorine bleach is gone. Mix 1 cup of cold water and 1 tablespoon of white vinegar in a container and soak the net mesh with the cysts for about one minute. This will remove or neutralize the residual chlorine bleach. Rinse the cysts one more time with fresh water. Your cysts are now ready for hatching!”
Chris Durkin
Soak 1 tsp. eggs in 3 oz. water for an hour with an airstone to keep them suspended. Add 2 oz. chlorine bleach and stir for 4 minutes. Pour into a brine shrimp net and rinse well. Add rinsed eggs to 8 oz. water with 1 tbs. vinegar added to neutralize bleach. Stir for 30 sec. to 1 min. Rinse again in brine shrimp net, hatch as usual.
Use cold water in the bleach step; the reaction produces heat, and if too much is generated, it could kill the artemia. You will notice the cysts turn from brown to rust-orange by the end of the bleaching. I have used this procedure many times and have always gotten very good results.
Jeff Bilbrough
“My experience with dechorinating (removing the chorion) from brine shrimp cysts in a solution of 50% each of bleach and water generates some degree of heat. With one cup each of bleach and water and one teaspoon to one tablespoon of cysts the heat generated seems to do no harm. I’ve tried a quarter cup of cysts in the same quantity of liquid and the container got quite hot.” The result was a poor hatch; the non-scientific conclusion was that the heat killed the cysts.
Decapsulating eggs may take a bit more time and trouble than simply hatching out nauplii, but use of those eggs which traditionally did not hatch may make the effort well worthwhile.
— G.C.K.A. Newsletter, May 2000 Return to top of page
An Easy Live Food: Microworms
On the whole, microworms are one of the most dependable and simplest of the live foods you can culture. With a minimum of attention, you, too, can have live food for your juvenile fish and fry, whenever you need it.
Nearly every aquarist, it seems, has a different recipe to culture microworms, but basically you need: a starter culture (available commercially, or from a fellow aquarist); a culture medium; water; regular baker’s yeast; and a suitable container.
Any appropriate plastic or glass container with a lid (to keep moisture in and pests out) is suitable for microwormsplastic cups, cottage cheese or margarine containers, plastic shoeboxes, etc.
The culture medium should be starch based. Most cultures are based on baby cereal (Hi-Protein, Rice, Oatmeal, etc.); instant mashed potato mix; or regular flour; but any good breakfast cereal without fruit will also work; as will cooked porridge; or a mix of cornmeal and whole-wheat flour. Some aquarists successfully raise microworms on well soaked white bread.
Add water to the culture material and mix it to make a thick slurry. Place 1/2″ to 3/4″ of the culture medium in the bottom of a suitable container, add a pinch of yeast and the starter culture and mix well. Put a cover loosely on the container and place where it will be moderately warm, 70-75F or so.
Wait a few days, then check the culture for activity. The culture is “working” properly when the surface shows a ripply, satiny appearance.
There are almost as many variants to collecting microworms for feeding to your fish as there are culture media. Among the recommended methods:
With your finger or a spoon, scrape off the layer of worms that have crawled up onto the sides of the container.
Soak a popsicle stick in water, then insert it into the container. The worms will crawl up onto the wood.
Or simply scrape off a bit of that top “working” layer. Any extra nutrients in the fry tank from the culture media will help support a culture of infusoria.
If you want to get a bit fancier with your microworm culture you can put the culture medium (Roger Sieloff uses flour and water) into glass jars, then use an autoclave to set the culture medium, drive off any chloramines, and sterilize it. Once cool, inoculate with starter culture. This method will produce a culture that will last approximately 3 weeks.
Since cultures will not continue indefinitely, most aquarists maintain several cultures at one time, and start new ones regularly. In addition, they add new culture media and/or yeast from time to time to keep existing cultures in production longer.
Several problems are often encountered with microworms: limited culture life, cultures going bad (souring, liquefying, or drying out) and dirtying of the tanks where they are fed.
To prevent your microworm cultures from failing completely, keep several cultures going at once, and start new ones on a regular basis. To avoid cultures drying out, keep the top covered before and after feeding, and occasionally stir in a little additional water. Be sure to use water with the chlorine removed, or a bit of tank water.
Sour, “funky” cultures can sometimes be revived by the addition of fresh media and yeast. For a discolored culture, scrape off the darkened top layer first. One aquarist suggests adding a pinch of baking soda when the culture gets “funky.” Occasionally, a culture will “liquefy,” with the top surface turning thin and runny, or developing a “skin”. Sometimes such a culture can be revived; sometimes nothing will help.
Some “dirtying” of tanks is inevitable when feeding microworms by all but the popsicle stick method. In most cases, this causes little problem, and actually benefits fry by providing nutrients for infusoria. To deal with the additional dirt, you may have to add a couple of snails, or step up your schedule of partial water changes.
— G.C.K.A. Newsletter, August 1997 Return to top of page
Feeding Our Fish
By Donna M. Recktenwalt
As aquarists, we know that feeding our fish a variety of quality foods is important, and we have developed a good feel for how much to feed at any given time.
To be healthy, fish require appropriate conditions (water, temperature, appropriate tank size, compatible companions), light, and food. Since an aquarium is an unnatural situation, the aquarist must also be observant, to see that all the fish are eating, not just the bolder individuals. If fish receive too little food or food inadequate to their nutritional needs, they will merely survive at the expense of good color, vitality, and reproduction.
Feeding fish is more than just dropping a pinch of dry food into the tank once or twice a day. For fish to be healthy and show their best colors, they require a diet that fulfills all their basic nutritional needs. If we want the fish to be well nourished, we need to understand their needs and requirements and feed them good food.
Like humans, fish require a diet containing a balanced mix of fats, carbohydrates, protein, vitamins, and minerals. If so inclined, the aquarist can make quality fish foods at home, using fresh or frozen ingredients and already proven formulae. However, most commercially available dry and flake foods meet basic piscine requirements and form a good basis for their diet. Lee Harper has used ground Purina Trout Chow as the basis for his fish feeding regimen for years. However, even for fish that are not being stressed by breeding, it’s a good idea to use a variety of formulations in addition to the occasional live foods, to provide variety.
How Much and How Often to Feed?
In nature, fish feed continually. In the aquarium, the aquarist controls the feeding cycle not only by the selection of foods, but by the choice of feeding times.
Most aquarists recommend feeding at least twice a day, with more frequent feedings for fry. With dry foods, feed as much as the fish will clean up in about five minutes; after that, most foods will begin to pollute the water. Some live foods, such as daphnia, glassworms, mosquito larvae, and bloodworms, may be left in the tank with the fish for “snacking” later. Tubifex worms may burrow into the substrate, out of reach of the fish. If not eaten in a day or two, mosquito larvae may reach their adult form; be forewarned that for them, the aquarist may make a good meal!
If you choose to feed only once a day, morning is preferable. In well planted aquaria or those with green water, chlorophyll in the plants generates oxygen (O2) in the presence of light and releases carbon dioxide (CO2) when dark. Fish require extra oxygen in order to aid digestion. Feeding early in the day assures that plenty of oxygen is available, particularly in aquaria with heavy fish loads. In aquaria withless fish, the actual feeding times are less critical.
Feeding Breeding Fish
Breeding fish are under greater nutritional stress than are fish merely maintained in an aquarium. In addition to meeting their own basic nutritional needs, they must also develop strong eggs and sperm, and have sufficient energy for courting and spawning. For breeding fish, the addition of live foods is highly recommended. However, observation by aquarists have shown that some live foods are more beneficial than others.
Brine Shrimp: Newly hatched brine shrimp nauplii are an excellent food for any killifish, from those newly hatched fry large enough to take them, up to breeding adults. However, egg production by adults fed solely on brine shrimp nauplii has often been minimal. Adult live or frozen brine shrimp are also good, although some loss of nutrition occurs during the thawing process.
Worms (earthworms, bloodworms, tubifex worms, whiteworms, etc.): Feeding worms has long been known to increase egg production in breeding fish. Earthworms, tubifex worms, glassworms, and whiteworms are particularly good, as are fresh or frozen bloodworms. Black- and tubifex worms have a dubious reputation, and should be used with care.
Mosquito Larvae: When available, this is probably one of the best possible live foods for any killifish.
Daphnia: When used with brine shrimp, daphnia can increase egg production, but not to the extent that tubifex will.
References: Speice, Paul. “Guppies to Groupers,” Freshwater and Marine Aquarium, January 1986.
— G. C. K. A. Newsletter, July 1998 Return to top of pageFeeding Killifish …
A Few Useful Recipes
Each aquarist who makes his own fishfood (and there are many who do) seems to have a preferred recipe that works well for his fish. The following are two proven homemade foods that have worked well.
Joe Dombkowski: Joe is mostly a cichlidiot, but this recipe would work for many fish that require a high proportion of herbivorous material in the diet. This is Joe’s “tried and true recipe: 50% spinach, 50% beef heart.”
Recipe: Put one pound beef heart into a food processor and grind to a pate. Add one pound frozen spinach and remix. Put mixture into cheesecloth and wring out excess moisture. Put mixture in a plastic bag, flatten, and freeze. Joe breaks off pieces and feeds it still frozen. (Thanks to the “Cichlid Sightings,” column by Jim Stigliano in the Greater Chicago Cichlid Association newsletter, GCCA Cichlid Chatter, January 1999).
Lee Harper: This recipe, adapted from Roger Hoelter’s recipe for Fishfood from a Gelatin Base, was published in the Novem ber 1998 newsletter of the Keystone Killy Group.
Recipe: 2 cans fish-based Friskies cat food or fresh fish (tuna, salmon, whitefish); 1 jar baby food (carrots); 4 packets Knox gelatin in 4 tbs. (or more) hot water. Optional – a bunch of fresh parsley or baby green beans; 1 can drained small cocktail shrimp or clams. Blend all ingredients but gelatin and water in blender until uniform. Heat gelatin and water, stir until dissolved (do not overheat!); pour into blender and mix for another minute. Pour into small plastic bags and freeze. To feed: grate a quantity of the frozen food and disperse into 1/2 cup water, then feed with an eye dropper or baster.– GCKA Newsletter, May 1999 Return to top of page
Feeding Killies –
Dry Food for Killifish
By Donna M. Recktenwalt
One of the complaints often heard about killifish is that they won’t eat dry food.
Not true. In fact, the staple food for many killikeepers is commercially produced dry foods. These are of various types, including flakes, freeze-dried, and pelleted forms. Of course, all fish will do better if they have variety in their diets, and breeding fish especially benefit from generous helpings of live foods.
“I have 26 varieties of plant-spawning killies,” John Burns writes. “The core diet I feed is Hikari Sinking Carnivore Pellets.” In a blender, he processes the pellets to a fine powder; this floats for a time, then remains in the water column for even longer. He feeds this to all his fish, with juveniles and adults receiving bloodworms as well. “They all ‘eat with gusto,’ ” says John.
“I’ve observed that most killies will eat ground up Purina Trout Chow [primary ingredient fish meal] but will not touch flake foods,” says Lee Harper. “They will also eat without much persuasion any of the dried shrimp, worms, etc. They apparently don’t care for cereal-based foods. In any circumstance, no one food should be used alone; a variety including live foods is essential.”
“Every killie I have ever kept has eaten flake food,” reports John van Rompu. “Some are reluctant at first, but after a few days they get the hang of it.” However, John agrees, “you must give them a varied diet. All my killies also receive at least one feeding of baby brine per day and in season, mosquito larvae, etc. Do not feed just one food if you want healthy robust fish.”
“I have raised more than 10 generations of Epiplatys dageti Monroviae on a basic diet of TetraMin, with irregular additions of frozen brine shrimp, live brine shrimp, and small earthworms,” says Bruce Stallsmith. “My Rivulus marmoratus, on the other hand, definitely need real ‘meat’ on a regular basis, although they take TetraMin too. Interestingly, wild-caught native Fundulus species will start eating TetraMin after several days in captivity.”
“Most killies will eat flake food,” agrees George Slusarczuk. “The best method to teach them to accept dry flake food is to start feeding early, when the fry are about 1/2″ long, one feeding a day. I usually feed dry food in the morning, when they are the hungriest.” George uses TetraMin Staple and TetraMin Ruby, crushed and sieved to proper size.
Sue Katz says that many of her killies relish OSI freshwater flake food. “Even many of the ‘well fed but picky’ fish … have transferred to eating the OSI. They’ve refused some of the other flake foods I’ve tried, so it might be something OSI alone has.”
“I don’t recall ever having a killi species that never eats dry food,” says Wright Huntley, “and I usually have close to 50 species around. Some new wild fish are tough to get going [on dry foods] but all others can be taught.” The trick is to introduce quality foods they will like, into a “feeding frenzy” situation. “I have found Brine Shrimp Direct brine shrimp flake to be accepted by all, once they know it is good to eat. Introducing it into the competition of the rearing tank is sure to get them going.”
“Many of my fish would just starve to death before eating the standard Wardley and Tetra flake stuff,” he continues, “I don’t know why.” Wright usually feeds mostly live foods, but includes dry foods of various types: micro-pellets, flake foods, etc., especially “right after vacations and field trips, when they are good and hungry.” That way, when the live food sources fail, the fish will still eat and remain healthy.
“My favorite food to teach babies to eat dry stuff is Hikari ‘Oranda Gold’ minipellets, ground in a hand pepper mill,” says Wright. “Most of it floats, but enough sinks to get them striking at it. Once they find out how good it tastes they are off and running. An advantage of the ‘Oranda Gold’ is the high quantity of color-enhancing algae in it.”
“Another good [starter] food is crushed spirulina pellets from either JBL or Tetra,” suggests David Skop. For smaller surface-feeding killifish fry, Artificial Plankton Rotifer (APR) is an invaluable early dry food, and high in fish protein. The fish will take it from the surface, or as it falls through the water.
– G.C.K.A. Newsletter, November 1999 Return to top of page
Foods for Small FryBy Donna M. Recktenwalt
Feeding small, newly hatched fry can be a problem, especially for those species whose fry are unusually tiny. The foods must small enough for the fry to take, they must palatable, nutritious, and fairly easy for the aquarist to use. There are a number of possibilities available. The following reviews a few of them.
One of the traditional standbys for feeding fry is newly hatched brine shrimp. These are nutritious food, and as active, free swimming larvae, most fry will take them with gusto. However, hatching out brine shrimp takes time, equipment, and attention. There are other answers.
“I wonder,” says Al Anderson, “if anyone remembers that before brine shrimp eggs we used to use boiled chicken egg yolk to start young fish with.”
An Old Standby – Egg Yolk
Boil an egg or two and remove the yolk, then store in the refrigerator.
When ready to feed, squish the egg yolk between your fingers or through a very fine sieve or linen handkerchief. Either mix the resulting material in water, or with your finger apply a bit to the water surface. Liquid vitamins can also be added to the egg yolk.
“Feed small amounts,” cautions Al, and make frequent water changes,” since it is easy to foul the water. As with other non-live foods, strong aeration is recommended.
Some Other Possibilities
Artificial Plankton, Rotifers. This finely powdered material can be mixed in water and fed to even the tiniest fry. “A little bit goes a long way,” says Tony Terceira. ” I simply mix a quarter teaspoon in a small jar, shake” vigorously, and then feed the resulting emulsion. Although made for saltwater use, the product is readily taken, and does not pollute the water.
Micron Fry Food. Extremely fine, thus suitable for very small fry, this product contains an assortment of microorganisms, and is readily taken.
Sanders Small Fry Gold. “I’ve been using this product with some success,” reports Donna Recktenwalt. It is an extremely fine powder that can either be fed dry on the surface or mixed into an emulsion. Small fry seem to do well on a combination of it and microworms. “Be sure to add a snail to help clean up any leftovers, and keep up the [frequent] water changes.”
Artemia Golden Pearls, or Decapsulated Brine Shrimp Eggs. You can decapsulate brine shrimp eggs yourself using unhatched cysts, or purchase them already processed.
“No,” cautions Wright Huntley, “the fish will not eat them cold. If you have been feeding baby brine shrimp so they know the taste and color, they’ll eagerly scarf them down. Just don’t expect them to be perceived as food by either those tiny babies that still need movement to trigger feeding, or any fish not accustomed to ‘small orange/pink things.’” “Of course,” Tony Terceira comments, “a little bit of everything will get some food into fry. Like all good practices, diversity of diet, and small water changes are the key to raising small fry.”
— G.C.K.A. Newsletter, December 2000 Return to top of page
Live Foods:
Fruit Flies – Drosophila melanogaster
We all know that live food on at least an occasional basis is one of the best things we can do to foster good health, good growth, and regular spawning in our killifish. But what live foods can we feed during the “off” seasons, when mosquito larvae aren’t available, and the daphnia cultures have gone dormant?
A regular standby of many aquarists is fruitflies. Most killifish will gladly accept them, as will many amphibians and reptiles.
“You’re raising WHAT in the house?”
If your spouse asks this, keep in mind that she or he has a legitimate concern. Ask anyone who has ever been plagued by a cloud of them around softening fruit. However, a larger, wingless strain of cultured fruit fly is now available which not only cannot fly, but is more prolific and will breed true unless contaminated by wild stock.
Sometimes this information alone is enough to overcome spousal resistance.
Containers for culturing fruit flies should be large enough to contain sufficient culture medium, but not too large to handle easily. Glass containers iced tea or juice bottles, or suitably sized canning jars are a good choice, and can be easily run through the dishwasher between uses. Plastic containers (2 liter soft drink bottles with the tops cut off, or juice/iced tea bottles) also work well, and can simply be recycled or thrown away when they have served their purpose.
Growth medium for fruit flies is a matter of preference. Fresh, decaying fruit or fruit based mixes will work, but tend to be smelly, messy, subject to mold and to attracting unwanted insects.
Commercially available cultures are easier to use and considerably neater to work with. The fruit fly medium from Carolina Biologicals is recommended by many. According to Barry Cooper, “You put a scoopful in the bottle, add an equal volume of water, wait a minute, add a sprinkle of yeast, then add the fly innoculum. Very easy.”
Alternatively, try using instant mashed potatoes. Several variations of the recipe are available, but all begin by preparing instant mashed potatoes according to label directions. Then:
1) add some sugar, a drop of blue food coloring (if you like), and some yeast. Sprinkling the yeast on top works better than mixing it in, which usually results in the culture “rising”; this can get messy. The result of this recipe is very similar to the culture medium sold by Carolina Biologicals, at a fraction of the expense.
2) add one tablespoon of sugar per cup of medium (brown sugar or cane syrup will also work) and a pinch of salt.
3) to the basic mixture you can also add flour, producing a “doughier” consistency. This can then be frozen into appropriately sized portions for later use.
For an entirely different recipe, try this one suggested by Art Abramovitch: add yeast to a quantity of beer; wait half an hour or so, then add dry baby food oatmeal to a consistency that is moist but not sticky.
Spoon your culture medium approximately one inch deep into containers and add a “scaffolding” for the flies to crawl on. Plastic fly screen from the hardware store, cut into strips, works well, as do popsicle sticks or crumpled paper.
Add fly culture innoculant, then cover the container using a piece of fine mesh cloth or old nylon stocking held in place with a rubber band; or a “plug” of cotton or plastic foam.
Feeding Fruit Flies
When preparing to dispense the adult flies, first rap on the side of the culture container once or twice to knock the flies to the bottom. Remove the cover, then GENTLY shake the flies out. Immediately recover the container, and be certain to cover the tank you’re feeding as well, to avoid escapees.
Known problems
The potato culture medium can get messy if bacteria cultures take hold before the yeast. To avoid this, try dissolving the yeast in aged dechorinated tap water, then add the instant mashed potatoes and the yeast on top. Let sit for a couple of days, then add the flies.
The culture also may develop mold. If the culture medium is too dry, mold is inhibited, but it may be difficult to remove the flies for feeding.Fly Larvae an untapped food source?
We don’t usually think of “maggots” in positive terms, but fruit fly larvae are as good a live food as their mature, adult relatives. This concept can be taken a step further, if you are adventuresome and willing to give it a try.
Ramon De La Cuetara of Puerto Rico suggests setting up outdoor fly cultures, using covered pint plastic containers with half inch holes cut in the lids. A culture medium of 1/2 teaspoon mashed potato powder and 1 tablespoon water is put into each container, and the container then set outside for about a week.
To harvest the larvae (Ramon says he gets mostly fruit flies, but sometimes housefly larvae as well), fill the container with water, stir the medium to dissolve it, then pour through a brine shrimp net. Wash in clear water, then feed as a free source of nutritious live food.
— GCKA Newsletter, December 1997 Return to top of page
Those who breed fish and raise fry are always interested in finding another food that can get those youngsters off to a good start. Rick Borstein, Editor of GCCA Cichlid Chatter, newsletter of the Greater Chicago Cichlid Association, writing in the July 1999 issue, recommends a new product. Cyclop-Eeze is powdered cyclops, a small rotifer. The product is appropriately sized to feed small fry and replaces brine shrimp nauplii.
To feed, sprinkle on the surface of the water. If the fry are clustered in one small area, simply mix some with water and squirt it into the appropriate location.
“I’ve never been very fond of raising baby brine shrimp–Artemia nauplii,” writes Rick. “When another member told me about Cyclop-Eeze, I immediately … bought a can. I love this stuff! I recently have fed it to Chalinochromis bifrentus and Petrotilapia nkhata fry with great success. The fry love it, and grow fast. Cyclop-Eeze is a revolutionary product because it lowers a significant barrier for beginners… [with] cichlids.”
If you can find this product, it might prove a very useful tool for raising killifish, as well.
— G.C.K.A. Newsletter, September 1999 Return to top of page
How I Do It … BabyBrine Shrimp
“I’ve never been happy with hatching out brine shrimp for the small number of fish I keep,” says Donna Recktenwalt. “I always had too many nauplii to feed properly in a short period of time, and setting up a hatching container for such a small amount was too much fuss.
Then she hit on a “bulk combination” method.
Hatch out a generous measure of brine shrimp eggs the usual way. Donna uses a half filled 2 gal. hex tank, into which is set a 2 liter pop bottle with the top cut off, filled with the eggs and hatching solution. She adds an airstone to keep the eggs moving, and leaves a light on above the “hatchery” for warmth.
When live, swimming nauplii are visible, she removes as many nauplii as possible, and cleans and feeds them the usual way. Any remaining nauplii are poured into cocktail sized ice cube trays and frozen. The remaining unhatched eggs are then decapsulated, rinsed, and also frozen. The ice cubes are stored in a sealed plastic bag. To feed, simply drop an appropriate number of the tiny ice cubes into each tank or container.
— G.C.K.A. Newsletter, March 2000 Return to top of page
Live Foods
Moths: Another Group of Live Foods
By A. Lexeyev
This article originally appeared in Rybovodstvo (a Russian magazine), #5,September/October 1985, p. 48.
Some people successfully breed various types of moth at home–they can be useful as food for the inhabitants of terrariums [or aquariums–Editor].
Cereal Moth (Ephestia kuehlniella)
Was brought to Europe from America in the 19th century and has become widespread since then. It is easy to find these tiny moths in cereals, flour, or bran.
An artificial culture of moths can be kept in plastic shoeboxes, no less than 1 liter. A tight lid is a must–it must have a small ventilation hole sealed by dense metal or plastic mesh. The shoebox is 2/3 filled with wheat flour or cornflakes, adding a few teaspoons of sugar and dry yeast. No more than 10 pairs of moths are loaded in 1 liter shoeboxes. It is recommended to run several cultures in parallel, since they may degenerate quickly. The optimal temperature for breeding moths is about 25°C (77°F). At these temperatures the eggs develop in four days, the larvae develop for 30-36 days, and pupae in 8 days. The moths reach sexual maturity when one day old.
Fruit Moth (Plodia interpunctella)
Similar to the cereal moth, it feeds on the remains of human food. This moth can be kept in similar conditions, except for using wheat grains as a substrate. The eggs develop in five days, larvae in 25-30, and pupae in 8. Sexual maturity is reached when one day old. It is recommended to add a small amount of dried fruits as a food for these moths.
Large Wax Moth (Galleria melonella) and Small Wax Moth (Achroia grisella)
Wax moths can be found anywhere near beehives and honeycombs, even old ones. Sometimes the two species can be found at the same time. It is recommended to cultivate the two species separately to avoid combination of one of them. The larvae of both species develop on wax, but they also require other products resulting from the lifespan of bees: pupae shells, excrement, propolis, etc. Before starting up a culture of wax moths, one should find out whether he will be able to have old honeycombs regularly. Wax moths are bred in plastic shoeboxes with tight lids (2/3 of the lid cut and covered with a mesh). The box is filled with paper or cardboard. Optimal temperature is around 28°C (85°F). Eggs develop in four days, larvae in 35, pupae in 7-9. Moths reach sexual maturity when 1-2 days old. To collect the larvae of large moths, paper or cardboard tubes are used; pieces of paper are laid on the surface of the substrate for collecting larvae of small wax moths. The larvae collect under such “shelters” to develop into pupae.
German experts recommend the following food for breeding moths: 100g of dry yeast, 200g of wheat flour paste, 200g of skimmed milk powder, 200g flour, 400g corn or semolina, 500g honey, and 500 g glycerin. The dry components are mixed first, then the mixture of honey and glycerin is added. This food can be kept for a long time in the refrigerator. Nut-sized balls can be made and several such balls wrapped in paper for feeding to the moths.
–G.C.K.A. Newsletter, December 1999 Return to top of page
Al Anderson is well known in the midwest for his skill at breeding exotic fish. To support them, he also breeds quantities of live foods, among them whiteworms.
“Whiteworms do best at 55-65ºF,” Al says. He cultures them on Magic Worm Bedding mixed according to directions, but at half the amount. He puts a dry layer on the bottom of the container (usually a large bucket), puts the culture in the center, then surrounds the edges with more dry bedding. He then feeds and waters in the center of the culture. To feed, he dunks break in tank water and lays it on top of the culture. The bread will keep, covered, in the refrigerator for a couple of days.
“Keep the worms in the dark,” he says, and they should do fine.
— G.C.K.A. Newsletter, December 2000. Return to top of page
Nutritive Additions … Spirulina
Aquarists know that dietary variety, including live foods, is important for inducing spawning condition and growing out strong, healthy fry.
One of the fishfood ingredients that has proven of great benefit is spirulina, a type of seaweed used in the formulation of many commercial fishfood products. It has been shown to help increase yellow colors and intensify reds, but has little effect on the metallic blues, which are guanine based.
Another way of getting spirulina into your fishes’ diets is to feed them live food organisms that have been fed with spirulina powder. This “gut loading” technique has been proven to work with a number of live food organisms, and with a number of additives.
“I feed my [grindal] worms [spirulina] flake a few hours prior to feeding the fish, then harvest the worms from the area where the food was,” says Karl Johnsen.
Richard Sexton feeds spirulina in a prepared food. “You can buy commercially available foods … or you can make your own mixture at home. I make one with a shrimp base and add assorted vegetables, etc.”
“I use spirulina powder to feed my daphnia culture, then an hour later feed the daphnia to my fish,” says Ross Cronkhite. “I’ve also added spirulina powder to my microworm culture. Everything, including the worms, turns (a really ugly) green. What surprised me was the intensification of the red color of the daphnia in the hour before feeding them to my fish.”
– GCKA Newsletter, May 1999 Return to top of page
Paste Foods – Another Alternative
Every aquarist has his or her own “recipe” for successfully feeding his/her fish, although almost all agree that variety in the diet will improve overall vigor, color, and health. Most successful aquarists rely on a combination of foods, including fresh or live foods, frozen foods, flake foods, and in some cases, paste foods.
Fresh foods are any of those you can prepare yourself, such as beef heart, shrimp, or clams. Live foods are those you can buy, grow, or catch yourself: daphnia, bloodworms, brine shrimp, mosquito larvae, earthworms, white worms, etc. A number of frozen and flake foods are available, some specialized for the nutritional needs of particular fish – cichlids, koi, goldfish, etc. Pellet foods are seldom used for killifish unless ground first, since most formulations are too large.
Paste foods, however, have long been a breeder’s standby, and can be used as a staple of the killifish diet. Most can be created fairly easily in the average kitchen using a blender and readily available ingredients.
A number of different recipes have been developed; we present two of the more popular ones.
Dale Deck’s Paste Food Recipe
3 pints water
1/2 lb. beef heart
1/2 lb. beef liver
1/4 lb. fish fillet
1 small can clams
8 oz. shrimp
1 tsp. Salt
2 c. oatmeal
1/2 c. Parmesan cheese
1 tsp. Anise oil
1 envelope Knox unflavored gelatin
Optional items include: 1 small can cat food, 1/2 c fish meal, 1/2 c shrimp meal, dried Krill, spinach, carrots, or anything else that is nutritious.
Boil all ingredients together until tender. Process in blender until smooth. Return to pot and bring to boil, then place in clean, heated jars and seal. Cool, then place in refrigerator. Do not freeze (makes the paste watery). Feed in small quantities.
Steve Shine’s Variation on Bower’s “Omnivore Diet”
5 oz. whole shrimp (less tails)
5 oz. haddock fillet
4 oz. crab meat
1 Tbl. Parsley
1 Tbl. carrot shavings
1 Tbl. green peas
1 Tbl. oatmeal
2 tsp. Brewer’s yeast
2-3 dashes Paprika
1 drop Anise extract
2 packets unflavored gelatin
1/2 tsp. Poly-Vi-Sol baby vitamins
Puree all ingredients but the gelatin with 2 oz. of water. Dissolve gelatin in 10 oz. boiling water. While running blender, slowly add dissolved gelatin to rest of mixture. If you want floating food, pour directly into a thin layer in zip lock bags. If you want sinking food, allow to sit for a while to allow air bubbles to escape. Lay the bags flat in the refrigerator to chill and set up for 24 hours. Do not put directly into the freezer, or the gelatin won’t set up properly! After 24 hours move containers into freezer. Cut frozen food into chunks or slices; thaw only what you need for a single feeding.
Note: If the consistency of the preparation seems too wet, add some flake food.
— G.C.K.A. Newsletter, June 1999 Return to top of page
Live Food
Puttin’ Live Food By or
Carryin’ That Summer Bounty Into Fall
Fall is here, and with it the eventual end of the bounty of live foods that we have been able to collect and/or culture outdoors through the warmer months. Some of these cultures can be brought inside for the winter and continue to produce live food for our killifish; others are done for the season, unavailable until next year.
But the end of good weather doesn’t necessarily mean the end of good food for your fish. With a little work and attention to detail, you can preserve some of that bountiful harvest for later use.
Freezing
Perhaps the simplest and best method for preserving most live foods available to the hobbyist is freezing. It is particularly good for such freshwater creatures as daphnia, mosquito larvae and eggs, bloodworms and tubifex. Brine shrimp will also freeze well, but few of us grow enough of them to adult sizes to bother. Before freezing, drain off most of the water using a net or strainer. It isn’t necessary to remove all of the water, but the more you remove the less space will be required in the freezer. Freeze in thin sheets or as small cubes in ice cube trays. Once solid, the material can be removed and stored in freezer bags. Feeding is simple: break off a piece and thaw, or drop directly into the tank.
Drying and Pickling
For animal matter that does not freeze well, such as insects and their larvae (such as mealworms), drying may be the best answer. Create a shallow “cage” using an aluminum pie or cake pan. On the bottom place a layer of aluminum foil with small holes poked through (to enhance air circulation), then a layer of metal window screening cut to fit inside the pan. A second piece of metal window screen should completely cover the top of the pan. Set your oven at 200-250F. Put the live food on the bottom screen, cover with the top screen, and put in the oven with the door left ajar so heat rises through the pan and out. Check every ten minutes or so. When a specimen breaks easily in half and shows no sign of moisture on the inside, drying is complete. The resulting food can be stored in screw-top jars in a cool, dry place until needed.
What about soft things, like slugs, earthworms, and the like? These can be pickled. Using rock or unspiced pickling salt, place as much as will dissolve easily into a pan of boiling water. Pour into sturdy, heated jars and cool slightly before adding the live food. The hot water will kill the creatures immediately. When the jars have cooled to near room temperature, screw on the lids. Refrigerate until use. Soak in fresh water for half an hour or so before feeding to remove excess salt.
Reference: Volkart, Bill, “Live Food,” Freshwater and Marine Aquarium, November 1990, pp. 59-62.
— GCKA Newsletter, November 1997 Return to top of page
Red/Black/Tubifex Worms – a Safe Food for Killies?
Long known as a quality food for fish, redworms, blackworms and tubifex worms are related tubificid species, each with its own benefits and drawbacks. The question is not one of palatability–most killifish will readily take any of them–but rather one of availability and cleanliness.
Some aquarists swear by blackworms as food for their fishes; others swear at them. The relative safety of the worms is in great part determined by where they are raised. Blackworms are coldwater dwellers that prefer well-oxygenated streams or running water. In California, many are produced in the settling lagoons of vegetable processors/canners, thriving in the stagnant wastewater. On trout farms, they often grow in the cool wastewater ponds, or in the mulm that accumulates on the screens blocking the raceways. The worms are harvested when the mulm is removed periodically to maintain water flow.
Redworms and tubifex worms prefer warmer, well enriched (nutrient dense) waters with a lower oxygen content, such as stagnant lagoons and sludge ponds.
“The addition of tubifex to a daily diet of brine shrimp increases egg production of killies–almost the next day!” reports Lee Harper, then cautions, “Black worms are easier to get and keep, but I almost always have had bad experiences with fish dying unexplainedly after feeding black worms.” The incidence may be small, but it always seems to be an irreplaceable fish that dies!
Responding to this, Richard Sexton agrees, but adds that white or grindal worms seem to be as good a food for boosting egg production as are tubifex.
Health Concerns
There have always been concerns about feeding black/red/tubifex worms to fish, since the worms often breed and grow in stagnant water and heavily polluted mud. There is a long circumstantial history of disease problems in tanks where they are fed, and tubificids are known to carry and transmit a simple single segment tapeworm that is of no consequence to aquarium fish.
“Regarding intestinal parasites and black/tubifex worms: I think you have to remember that fish fed on worms eat more and therefore excrete more,” says Barry Cooper. Whether the worms are causative of disease or not, “without rigorous water changes and tank cleaning this would make the fish vulnerable to all sorts of bacterial infections.”
Richard Sexton counters this observation. “I can have spotlessly clean tanks with daily water changes but feed worms, and there are diseases that I don’t get when I don’t feed worms. This has been observed over a long period of time. On the other hand, I’ve seen fish live in all manner of …[dirt] but never get the hemorrhagic septicemia outbreaks that accompany worms,” and those oubtreaks always seemed to be proportional to the amount of worms fed.
Keeping Blackworms
Blackworms are supposedly easy to maintain and raise, with the potential of doubling the population every month or so. “Blackworms are available at my local fish shops, just not reliably,” says Steve Halbasch. “When they are available I purchase a rather large supply (up to 8 oz.),” and keep them in a 10 gal. unheated container in the basement (water temperature 60-70°F), with an airstone to keep the water moving, and weekly 30-50% water changes. To feed the worms he adds thinly sliced raw potatoes.
“Usually when I get in blackworms,” says Rodney Harper, “they go outside into several 100g PVC vats” with a substrate of local clean white sand, where they remain until all used up. “I have never had any problems.”
“I rely extensively on blackworms to feed my adult killies, probably 50% of their diet,” says Eric Lund. “I wash them every other day or so in addition to before use.” They are kept in the crisper section of a refrigerator at about 38-40°F, with plenty of water volume. “To me they are indispensable for keeping larger killies (like OCC, SJO, Pterolebias and the larger Cynolebias). As a bonus, the worms establish themselves in the planted tanks (with a gravel substrate) and provide the occasional snack as they feed on detritus in the substrate.”
“My … bad experiences with blackworms are obviously at variance with some peoples’ experiences,” comments Lee Harper. “It is just another example that there are no absolute facts in killifish keeping–only what works for you.” Lee keeps his blackworms in refrigerator trays at 40-45°F, washing them several times on the first day, then morning and evening for several days, with changes every several days after that. “I never keep them more than 6 or 7 days. [The] … worms keep well under these conditions, unless they arrive in poor shape.”
Robert Nahn maintains seven ten gallon tanks where he raises red and tubifex worms for use in his fishroom. The tanks contain a 1.5 in. layer of fine sand substrate, are equipped with air-driven small corner filters, and contain numerous snails and healthy numbers of daphnia. He feeds spirulina pellets every other day, usually right after harvesting worms and/or daphnia. He harvests worms every other day, collecting from only one side of one tank each time; this way the majority of the cultures are untouched for nearly two weeks at a time. He scoops the sand out with a cup and pours it into a 1 gallon shoe box, then stirs the sand. The worms collect into a loose mass; the sand is returned to the tank.
Blackworms often arrive with accompanying gray-white leeches. If you feed the worms in a semi-wet state from a plastic container, the leeches will often adhere to the plastic. The few that do get into the tanks will do little harm. A Clorox rinse eliminates the rest.
– G.C.K.A. Newsletter, February 1999 Return to top of page
Live Foods
Vinegar Eels
One of the simplest live foods aquarists can raise to feed small fish and fry are vinegar eels. These are small worms, about a millimeter long as adults, about the same size as microworms. They tend to swim suspended in the culture liquid, with the greatest concentration visible as a cloudiness in the upper layers.
Vinegar eels can easily be cultured in the fishroom using loosely covered one gallon pickle jars. The cover may be a saucer set on top, a piece of aluminum foil, or a coffee filter or piece of clean material such as old pantyhose or t-shirt, held in place with a rubber band. The cover serves mostly to keep out unwanted pests.
The culture medium consists of equal parts cider vinegar and dechlorinated or tank water, with the addition of either a teaspoon of sugar per quart or a couple of slices of apple. They will appreciate the occasional feeding, but cultures can be safely ignored for months at a time, being long-lived, unusually care free and having no special rquirements.
Harvesting and Feeding
Perhaps the most difficult part of feeding vinegar eels is separating them from their culture medium. Several methods have proven successful, but perhaps the simplest is to suspend a nylon scouring pad (normally used in the kitchen for scrubbing dishes) or a clean piece of nylon stocking or pantyhose in the culture. When you’re ready to feed, remove the material from the culture medium, let it drip for a few minutes or squeeze out gently, then swish in a half cup or so of dechlorinated water. This liquid can then be fed to the fry. Acid buildup from the small amount of vinegar introduced by this method seems to be minor.
Eels can also be recovered by filtering, using a lab or coffee filter, a fine mesh net, or a tightly woven handkerchief. Simply pour a measure of the culture medium through the filter. After returning the liquid to the culture container, rinse out the filter material in water and feed the resulting liquid. Although slower than the scouring pad technique, this method is equally effective.
— G.C.K.A. Newsletter, March 1998 Return to top of page
Another Live Food
Yumm … Mosquitoes!
It has long been known among killikeepers that one of the best foods for killifish is mosquito larvae. With the season imminent, it seems a good time for discussion.
Mosquito larvae are generally found in standing, shallow water. Look in out of the way placesponds, puddles, and ditches, deep tire tracks, inside old tires, or in cans and containers left outside. The larvae are small, usually dark colored, “fuzzy” wrigglers that swim with a distinctive abrupt motion. They tend to hang at the surface for long periods, occasionally startling and dashing to the bottom, and can be quickly and easily netted and transferred to a waiting container of water.
The larvae can be fed at any stage of development. The egg rafts (which look like clumps of tiny dark brown cigars floating on the surface) can be dried for later hatching, and both the eggs and the larvae can be frozen for later use.
Don’t feel like tramping through the wilds? You can easily culture your own supply of mosquito larvae. Place a container of old water (the chemistry doesn’t seem to matter) in an out-of-the-way place outside and wait. If they are the water is still, the mosquitoes will find it. You can attract them by “steeping” a handful of fresh grass clippings in the container, or by adding some old leaves or a bit of powdered milk.
Egg rafts will soon appear, followed by larvae.
“I have a few ‘sweater boxes’ outside all year,” says Bob Schraedley. “They’re under a tree and get plenty of leaves dropping into them to create the right environment. I collect daphnia about nine months of the year from these. They freeze up in the fall, but the daphnia always come back right after the thaw. Rather than let the mosquito larvae take over … I collect the egg rafts a couple of times a week. These I put into a one gallon pickle jar and feed very fine flake fish food as they start to hatch.” You can raise them to whatever size you like.
George Davis prefers to “bring the egg rafts inside to grow … in 1/2 gallon apple juice jars full of green water. They are much easier to catch this way, and it avoids other unknown critters. In order to prevent the larvae from maturing … I occasionally ‘vacation’ a few A. linneatus right in the [culture] containers. Clears that problem right up, and returns some fat and happy killis. [However,] I wouldn’t recommend putting your prize killis outside, where kids, cats or raccoons might get to them.”
There Are a Few Cautions, However …
Not all mosquito species bite, but most do. In deference to household peace, be certain to feed only larvae that will be consumed before they have the chance to pupate. The pupae are distinctive: large, round headed, and with a hard shell. “I only feed the pupae to my larger fish and my Nothos, who are always eager and tackle them with gusto,” says Donna Recktenwalt.
— G.C.K.A. Newsletter, June 1998 Return to top of page
Whiteworms the Easy Way
By Tom Cook
After several years of tinkering and lots of reading and experimenting, I have finally come up with a “no mess, no hassle” formula for raising whiteworms. But fist, I’ll describe the traditional method of raising these little critters.
White worms are terrestrial worms that grow to about 1-1.5 inches in length and live in the soil near leftover food sources. They grow and breed very rapidly, so in a matter of about 6-8 weeks you can have a good culture going to start feeding to your meat eating fishes. long ago, aquarists found that you could raise whiteworms in a box of soil, and if kept fed, there would be an almost endless supply of live food available for their fishes.
The traditional method of raising them is as follows: Take a small container and fill it with garden soil, some peat moss or leaf loam and mix it thoroughly, making sure that it is light and airy. Moisten the soil so that it is damp but not muddy. Get a starter culture and feed it with a slice of potato, some leftover fruit, or even some bread or cereal. Remember, they are just getting started, so feed very sparingly. Either put a layer of soil over the food or place a dish or piece of glass on top of the food. The glass is a better idea since you can see how much food has been eaten. If you overfeed the food will spoil and ruin your culture. If the food is gone you can tell when to feed again. After about six weeks the container should be loaded with enough worms to start feeding your fishes. Many people recommend starting new culture about every six months to avoid having the soil go “sour.” Whiteworms do best if they can be kept cool (55-65F).
There are two major drawbacks to this method of culturing whiteworms.
The first problem comes when you try to get the worms separated from the soil. I have tried sifting them out, but the soil is usually too damp for this method to work. I read somewhere that you can wash them to get rid of the dirt, but it was very difficult to get them separated from the dirt without losing a large percentage down the drain.
The second problem I encountered trying this method was an infestation of mites. After a few months the culture always seemed to have more mites than worms, and if I tried to start a new culture, some mites always seemed to go along with the worms. I have been told that if you keep the culture surrounded by water that the mites can’t get to them, so that is a possible solution to this problem.
The method I have used recently has made me much more successful in raising whiteworms, and it’s also a lot easier as far as I’m concerned.
First, get one or two plastic shoe boxes and some sculptured foam rubber (such as is used for packing material). Cut the foam to fit the inside of the shoebox, and put about 1/2″ of cool water in the box. Get some whiteworms and add them to this box, feeding lightly with some dry baby food oatmeal (very cheap), and cover. Keep in a cool place. I have an extra refrigerator in which I moved the temperature probe from the refrigerator section to the freezer section, so that I can set it to about 60F). Check the culture every three days or so to see when the whiteworms need more food. I also drain the water and replace it with fresh water every couple of weeks to remove the ammonia (the worms need fresh surroundings just like the fish do) and any other harmful byproducts.
When the food starts being eaten in about a day, there should be enough worms to start using them. Removing the worms is a simple matter of draining the foam, placing it on the shoebox lid and shining a light on top of it about 4-6″ away. The heat from the light will drive the worms down to the bottom of the foam and out onto the plastic lid. I then use a tweezers to gather large masses of the worms and put them in a glass jar with water to feed as needed to each of my tanks.
By the way, after a few months the worms eat a lot of the oatmeal, so make sure you don’t underfeed them. The food is above the waterline so it doesn’t spoil nearly as fast as it does in dirt. Since you will be changing the water regularly, I have found no need to start new cultures, and my first one is still going strong.
— G.C.K.A. Newsletter – September 1996 Return to top of page
You, Too, Can Feed Live FoodsBy Donna M. Recktenwalt
We all know that live foods for our killifish can improve health and vigor, intensify color, and boost both egg production and the viability of the resulting fry. But how can the average killikeeper feed live foods without raising them himself? Brine shrimp are available at some aquarium stores, but often are of poor quality and high price. “Packets” of refrigerated live foods are sometimes available, but are pricey for even a moderate-sized fishroom.
With the arrival of warm weather, live foods for your killies may be as close as your neighborhood pond. There you may find mosquito larvae, daphnia, and perhaps some bloodworms. Your own backyard vegetable or flower garden or compost heap may yield earthworms, aphids, and ants.
Mosquito larvae are perhaps the most easily collected of the warm weather live foods. The larvae of several species of mosquitoes, they range from pale gray to almost black in color (with a few that surprise you by being green or purple) and are good food from the time they hatch until they break free of their pupae as adults. Both daphnia and mosquito larvae usually prefer sheltered, quiet water. Most aquarists who collect their own live foods recommend still, seasonal ponds, with temporary woodland pools being particularly rich, but ditches and puddles have also proven fruitful sources. Use a fine net and move it in a figure eight pattern.
Mosquito larvae are an excellent fish food, but a few precautions should be noted. The hard, nearly round pupae should only be fed to large, hungry fish. Otherwise, you may find your fishroom and house infested with bothersome, buzzing, biting visitors. And watch out for dragonfly larvae. These look similar to mosquito larvae, but are larger. They are voracious feeders and can wreak havoc in an aquarium full of small fish.
Mosquito larvae can be cultured, as well as collected. Fill a container with rainwater, set it in an area where it will be out of the way, then add your choice of: a few old leaves; a handful of grass clippings; or a measure of skim, regular, or evaporated milk. You will know that mosquitoes have found it when you find the tiny “rafts” of eggs, which look like clumps of miniature cigars floating on the surface of the water. These rafts may be placed directly into the tanks of small fish; as the larvae hatch the fish will find them.
Daphnia are a free-swimming, filter feeding crustacean that breeds prolifically under the correct conditions. Daphnia can often be collected from the same pools that yield mosquito larvae. Daphnia can be cultured in containers placed in sunny locations and fed regularly. Daphnia are filter feeders, so require a rich growth medium for their microscopic food. Horse manure or Miracle Gro fertilizer in the water will foster good growth of “green water” algae. Other foods for daphnia include: a sugar, flour and yeast mixture; strained baby food peas or sweet potatoes; pea or potato soup mix, etc. All of these should be mixed with water and enough added to the culture to produce “cloudy” water. When it turns clear, it’s time to feed again.
Aphids are the small, usually green or black sucking insects that infest rose buds and other tender growth on plants. Aphids make a welcome addition to a fish’s diet. Small numbers may simply be scraped off their host plant and fed. Larger numbers can be collected by sweeping a fine-mesh net through suitable vegetation. Alternatively, pieces of the host plants can be clipped and temporarily emersed directly in the tank.
Ants are a major part of the diet of many killifish species in their native habitats. Collecting them may be an unpleasant chore, but if you accidentally break into a nest and find a cluster of the white eggs and larvae, your killifish will relish them.
Small earthworms are always welcomed, especially by the larger killifish. If the worms are too large to feed whole, simply chop them up into smaller pieces using an old razor blade or scissors. Blue Gularis will gorge on earthworms, and even some of the more timid species will actively fight for them.
— G.C.K.A. Newsletter, July 1997 Return to top of page
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