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The Fishroom Library Archives —
Articles on Foods (live and otherwise) and Feeding Killifish (2001-2005)
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.
Another Fish Food Recipe – primarily vegetarian
Another Gelatin Recipe – Paste Foods, Revisited
Another Live Food – Crickets
Blackworms – more than you ever wanted to know, from Charles Nunziata.
Decapsulating Brine Shrimp Eggs
Enriching Brine Shrimp nauplii
Raising Adult Brine Shrimp
Confused Flour Beetles – revisited.
Can You Overwinter Daphnia?
Feeding Daphnia – from the fishroom, and from the kitchen.
How I Raise Daphnia – Bill Childers’ method.
Raising Daphnia – one man’s method.
Raising Daphnia – by the pound! How Milward Lavin did it in 1931.
Raising Daphnia – Bill Childers’ method.
Earthworms as Fish Food.
Easy Keepers – use a food slurry for raising fry
Feeding Our Fish
A Couple of Recipes for Frozen Fish Food – two recipes to try.
Fruit Flies – revisited, according to Cal Hin.
Another Method for Fruit Flies – Tom Cook’s technique
Garlic is more than Seasoning
Culturing Greenwater – additional techniques.
Grindal Worms – an old standby.
What is Infusoria?
Live Foods – an overview by several experienced aquarists
Homemade Paste Fish Food – another variation
Raising Worms on Foam – An additional method for grindals
Rotifers 101 – a beginner’s guide.
A Supplemental Fry Food – Resting Rotifers
Springtails – another possible live food.
What Do You Feed Your Worms?
Another Fish Food Recipe
Thanks to Robert E. Rueven, on the KillieTalk Mailing List.
Looking for a basically vegetable recipe for fish food? Consider this one, which uses primarily vegetable ingredients (organic vegetables preferred).
3 cups cooked oatmeal
1 med. steamed Idaho potato
1 med. steamed Sweet Potato (or Yam)
1 head steamed Romaine lettuce (all parts)
1/2 lb. steamed (frozen) green peas
1/2 lb. steamed (frozen) green beans
1/4 jar. wheat germ
1 lb. steamed Codfish
1/2 steamed red bell pepper (without seeds)
16 individual packets Knox gelatin (about 4 boxes)
2-3 cups boiling water
Steam ingredients, then mix in a blender (use juice from steam for blending) until you get a thick mush. Dissolve gelatin in 2-3 cups boiling water, then mix into vegetable mixture. Freeze until just firm, then slice into convenient sized chunks for feeding. Freeze solid.
— G.C.K.A. Newsletter – October 2003 Return to top of page
Another Gelatin Recipe …
Paste Foods, Revisited
Many killikeepers like to make their own foods, often using one of the readily available “paste” recipes. The following comes from John Hoernig (thanks to the electronic killietalk mailing list).
John learned the original recipe from his local aquarium club, Singing Sands Aquarium Society in Michigan City, Indiana, and modified the original recipe/method to save time in preparation and cleanup.
Ingredients
Baby food (in jars) – Buy types to suit the types of fish you are feeding. Peas, squash, complete meals, etc.
Knox Gelatin (in packets) – This is the binder and also an important food. Add about 1/2 the water the packet instructs. The liquid in the baby foods will provide the additional liquid. If using dry ingredients, you may need to add more water.
Multi Vitamins – Optional. John uses a generic but fresh multi-vitamin, crushed into a powder using a mortar and pestle.
Anything else you want to add – Chopped frozen spinach, beef hearts, turkey hearts, chicken hearts, etc. John says he doesn’t bother to do this, since there are plenty of baby foods available to fill any dietary requirement.
Preparation Method
Place all ingredients (except vitamins) in a microwave-safe Ziploc bag and mix thoroughly. Microwave until hot (the gelatin doesn’t need to cook, only to get hot). Mix in the vitamin powder.
Lay the bag out on a cookie sheet and freeze.
Feeding
Using a cheese grater, shred the amount of food you need into a bowl. You can feed this shredded material directly with your fingers. Or you can add water, then rinse through a net (save the rinse water) and place the resulting “goop” in a clean squeeze bottle (a small catsup bottle works well) for delivery.
If you’re feeding small fish, drain the rinse water through a brine shrimp net to recover the smaller pieces, then drain and feed the same way.
— G.C.K.A. Newsletter, April 2002 Return to top of page
Crickets make good critter (and killifish) food, especially pinhead (baby) crickets.
You can buy fairly well grown or adult crickets (dearly) at your local pet store. Or you can (fairly cheaply) grow your own, with minimal time and using minimal resources.
Mach Fukada, from Hawaii, reports that he has cultured crickets by collecting local insects, then placing them into a 5 gallon plastic bucket with about 3-4 inches of sand on the bottom. He fed them cabbage, dog food and rabbit food.
“I would place a bunch of scrunched up newspaper into the bucket to serve as a refugium for the pinhead crickets,” he says. “When I needed to harvest them I would just shake the newspaper into another bucket … and aspirate all that I needed.” His cricket hatchery was covered by windowscreen, held in place with Bungee cord.
In his article “Crickets as Killie Food,” Jim Robinson of the Canadian Killifish Association outlines another method. You will need, he says:
2 – new 10 gallon fish tanks
cellophane tape
3 – large Kritter Keepers
5 – plastic glasses
2 – clamp-on lights
2 – 100w light bulbs
margarine containers with lids
10 – shallow containers
egg cartons
used peat moss
net for squeezing out the peat moss
paper towels
starter crickets
First, determine your how many crickets you will need. You should plan to produce slightly more crickets than that, so you can grow a few from each batch to serve as breeders for the next generation. Each female will produce 10-20 eggs per day. Conservatively, 10 females will produce about 700 eggs per week, resulting in newly hatched crickets about the size of a fruit fly.
The Initial Setup
Take a new 10-gallon tank and put a strip of cellophane tape from top to bottom on the inside in each corner, smooth side out. (Crickets can’t climb glass, but they can climb silicone sealant or scratches in the glass.)
Place the egg cartons at one end of the tank (hiding place for the breeders). Attach the clamp-on light about 10″ above them.
Place a shallow container in the tank and cover with food. Make a continuous water supply by folding 2 paper towels to fit inside another shallow container. Fill a plastic glass full of water, place the lid with the paper towels over the top of the glass and invert quickly; place in the aquarium.
For the breeding medium, wash used peat thoroughly with hot water, then squeeze until very little water is dripping. Place this in another container and put in the tank.
Add your starter crickets. These can come from a live food supplier, your local pet store, or your own back yard. The species is less important than the fact you have crickets to work with.
Regular Maintenance
After several days, remove the used peat and replace.
Add a thin layer of damp peat on top of the used peat (to replace some of the lost moisture). Cover the container with a lid and mark with the hatching due date. Hatching time is dependent on temperature; at 80ºF incubation for commercial strain feeder crickets is about 12 days.
When the eggs are due to hatch, remove the lid and place the peat container into a Kritter Keeper that has been supplied with food and water. By keeping the hatchlings unlighted (cooler) they grow more slowly and can be fed to the fish for a longer period. Jim keeps about 4 spawns of crickets in one container for about three weeks.
Any young crickets left over after that time are placed into another prepared 10 gallon tank and allowed to grow up as breeders. At 6-8 weeks old, these young crickets are moved into the original breeding setup and the cycle continues. If the colony fails, you can always start up again with new crickets.
What do you feed your crickets? Commercial producers use a variety of specialty foods to enhance growth rates and foster better, more productive breeders, but crickets seem to do just fine on more ordinary fare. “One of the best things you can feed your crickets is flake food,” says Scott McLaughlin. “Use the highest protein content you can … and this will ‘gut load’ the crickets, allegedly passing on the nutrition to the fish.”
The Downside of Raising Crickets
Alas, no live food is perfect.
- Adult crickets chirp. You’ll always have at least some adults (breeders),
and they can get noisy. - Crickets are always trying to escape. Occasionally they succeed.
- Crickets require regular (if minimal) attention.
- They require a certain amount of space.
If you can only spend minimal time in your fishroom, crickets may not be for you. If you have a small house, or a house without a basement, or if you have family members who are averse to the occasional loose “bug,” crickets may not be for you. But if you have the space, and the inclination, they can provide an excellent live food for your killifish.
— G.C.K.A. Newsletter, April 2002 Return to top of page
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
Decapsulating Brine Shrimp Eggs
Hatching brine shrimp eggs can be a messy, time-consuming business. In the last few years, fishkeepers have discovered that decapsulating brine shrimp eggs eliminates the mess of floating shells and allows for quicker hatching and for the use of cysts that would not hatch at all.
Here’s how Ralph Tepedino does it.
- Soak the eggs in fresh water with about a teaspoon of eggs to each 3 ounces of water. An hour is long enough.
- Add an airstone to the container.
- Add 2 oz. of chlorine bleach (no additives).
- Keep the airstone in the mixture for 4 to 5 minutes. You will see the shells dissolve and turn from brown to orange.
- Now pour the mixture through a brine shrimp net and rinse with fresh water. You can also add a dechlorinater at this stage.
- When you are certain the decapsulated eggs are well rinsed, you can feed them as is (some fish will eat them, some won’t), or you can try hatching them the usual way.
“A number of years ago I used this method to try to hatch eggs that I had from 14 years prior. The outer shell came off ok, and they were a nice color, but they just wouldn’t hatch in brine solution,” Ralph says.
Since then, we’ve learned that many fish will eat these unhatched, decapsulated cysts anyway. They simply have to learn that those little orange specks are food, even though they don’t move in the water column.
– G.C.K.A. Newsletter, March 2004 Return to top of page
Confused Flour Beetles
Confused Flour Beetles are one of the simplest live foods to culture, and both larvae and adults make good food for fish. In a shallow covered container pour an inch or so of wheat flour (some add powdered milk). Add the adult beetles and a small piece of apple or potato for moisture. To remove beetles and larvae for feeding, sift the flour with a strainer. Always retain a few adults to continue the culture, and be sure to change part of media occasionally to keep the culture fresh. Always keep the culture covered – these beetles will escape if they can and get into your foodstuffs.
—G.C.K.A. Newsletter, May 2002 Return to top of page
Greenwater is a blessing, or a curse, depending on your point of view. To fishkeepers who want to maintain a pristine, clear tank, greenwater can be a real problem. To those who are trying to culture greenwater to feed fry or a daphnia colony, greenwater is a valued commodity. Many aquarists feel that tanks devoted to greenwater production are not “lost space,” but do double duty: they offer a space to start fry off well, to condition breeding females, or to offer respite for battered males. If you’re removing greenwater regularly, you’re also doing regular water changes, which benefit any fish that may be present.
Greenwater, whether desirable or not, flourishes when there is an overabundance of light and an excess of nutrients.
There is no “one way” to culture greenwater. Sometimes its occurrence is serendipitous. Other times, the aquarist has to “encourage” its development.
The easiest way to culture greenwater is to put several feeder goldfish in a 10 gallon tank, feed well several times a day, and leave the light on all the time. This will result in a “pea soup” mixture of various micro-critters and algae.
You can also start with “change water” from your tanks, left under a day-long light source. To it add any of the following:
- A pinch of “Miracle Gro” fertilizer.
- A starter from a jar with a “ring” of green on the bottom, or some green colored water.
- A teaspoon of dirt from your garden and some liquid fertilizer drops.
- A few pellets of “clean” manure (goat, sheep, rabbit, or deer) and some grass clippings or lettuce leaves.
- Some yard lime and a pinch of tomato fertilizer.
- Some grass and dandelions.
The above “recipes” will produce greenwater with “mixed” colonies, especially if they are kept outside. These may yield, in addition to greenwater and various microfauna, mosquito larvae, ostracods, cyclops, and daphnia. These can be harvested by straining the greenwater through a fine mesh net and rinsing off the result. Be certain to feed metamorphosing mosquito larvae (they look like hard “commas”) to eager big fish, otherwise they will hatch out into mosquitoes! This can be disruptive to serene home life!
You may wish to raise “pure” cultures. These should be started with a clean gallon jar of conditioned, dechlorinated water placed under strong light. Once the green culture has begun, you may want to add some slow aeration.
For Euglena–add several rabbit food pellets and a small piece or two of dried lettuce. Add a slow flowing airstone. Give continuous light. Remove some green water to feed, replenish with new water, and add a few rabbit pellets once in a while to keep the culture deep green.
For Paramecium–start with a few rabbit pellets. Add the pure paramecium culture. In a few days the culture will smell like a pond and will have clouds of little “bugs” near the surface. Scoop them out and feed.
– G.C.K.A. Newsletter, June 2003 Return to top of page
How I Do It …
Raising Daphnia
Daphnia is fairly easy to culture, but there seem to be as many different successful methods as there are aquarists.
“My suggestion,” says Harry Kuhman, “is to split [your starter culture] … into as many containers as you can. I put my starter in several one gallon jars on a windowsill and a fishless plant tank. Use aged water from as many different sources as you can, green water if you have it. This step is to keep the culture from dying out, as it sometimes will without apparent reason.
“Next set up some large containers for growing the critters.” Harry uses 30 gallon plastic trash cans as well as 5 gallon buckets. Do whatever is necessary to dechlorinate your water; well water, pond water, tank water, etc. are usually no problem. “Introduce a small amount of the daphnia to each container. If you don’t have green water you’ll need to feed the critters. My recommended first food is baker’s yeast. If you have the refrigerated cakes of yeast, just break off a little, dissolve it in a small amount of water, and add to the container.” For dry yeast, put some in a cup, add 1/4 to 1/2 tsp. sugar, fill with warm water and wait until the mixture froths, then feed a little to each container.
“Many other items can be used to feed as well. I sometimes put some lettuce in the blender and turn it into a nice green soup.” Try different things in different containers. Even when something works well, avoid feeding it to all the containers; sometimes it takes days for the full (not always good) effect to be seen.
For a few weeks you’ll likely have only modest amounts of daphnia, but they should begin to propagate. Continue to introduce them into containers that don’t seem to be doing much. After a while you should notice large numbers in the containers, eventually even a “bloom,” a heavy cloud of daphnia. “It’s particularly important to harvest when you get a bloom,” Harvey says, “usually shortly after feeding them, as they can overcrowd the container.”
Raising daphnia “really doesn’t take much effort,” he says. During the warm months you may even find a bonus in the culture in the form of mosquito larvae. “I encourage this in some [containers],” Harry says. “The fish like the mosquito larvae even more than daphnia.”
And we all know how our fish just love live foods!
— G.C.K.A. Newsletter, November 2001 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
Raising Daphnia … by the pound(?!)
“Much ridiculous nonsense has been written about raising daphnia,” Milward Lavin wrote back in 1931. More than 70 years later, his statement is still true.
“To raise daphnia, you have to know what you are doing,” and it all comes down to common sense.
Daphnia must have clean water with lots of oxygen, supplied either by plant life or compressed air. “The way to any animal’s heart is through its stomach,” and daphnia will eat nothing but infusoria. This food source must be cultured separately and fed on bacteria, so we must start with a culture suitable for bacteria.
Bacteria culture
To one gallon of water, add 5 beef bouillon cubes or 5 level teaspoons of beef extract. Boil the mixture for five minutes and allow to cool, then dissolve in it a level teaspoon of lye (sodium hydroxide). Be sure to use only a level teaspoon. Keep the solution in a dark place, open and uncovered, adding replacement water as required until you begin to use the culture. The culture will grow at 65-76° F, but will grow best at 98° F.
In three weeks to a month the culture will develop a scum on the surface; this scum is the infusoria.
Fill another tub with water and let it stand overnight to reach room temperature. Using a small very fine mesh net (nylon or silk) skim off the infusoria scum and place in the second tub. They will multiply more rapidly in the cleaner water.
Every two days, take a tumblerful of bacteria solution and pour it into the infusoria tub. Keep the tub uncovered and in the light at room temperature. Some water plants will help keep the water fresh.
For the Daphnia
Get another tub, a big one. Fill with water and add water plants or an airstone to supply oxygen. Place a few daphnia in the tub. Every two days use your fine mesh net to skim the infusoria culture and feed it to the daphnia. You should soon have a healthy colony of daphnia.
But don’t forget to keep the bacteria solution going. It takes a month to breed a batch of bacteria, so when the original bacteria culture is half used, start another one. If you run out of bacteria culture, the infusoria will starve, and then the daphnia will fail. Don’t make more than a gallon of bacteria solution at one time, and make sure that it never becomes more than 2 months old (cultures older than that will be useless). A glass of bacteria solution from the first culture will help start off the second one.
Remember, the system consists of three separate parts: bacteria; infusoria; and daphnia. You can’t combine any of these. If you try, all will fail, since they require different culture solutions and conditions.
– G.C.K.A. Newsletter, June 2005 Return to top of page
How I Raise Daphnia
“Live foods,” says Bill Childers, “can provide that extra boost that moves you from ‘keeping them alive’ toward ‘enticing them to breed’.” This is a major distinction between the casual fishkeeper and the aquarist who wants to successfully breed his fish and raise healthy fry.
We all know that success with aquarium fish involves a number of factors: good water quality, sufficient space, proper temperature, fish compatibility, and good food.
“One of my favorite live foods,” he continues, “is Daphnia.” These freshwater “bugs, sometimes called water fleas, are easy to culture if you understand their requirements. Daphnia feed by filtering small edible materials from the water. “What kind of stuff? Just about any kind of plant or animal life form that is small enough and moves about or is suspended in their water, thus
Rule No. 1. Do NOT put a filter in a daphnia tank. Bill uses an airline, bubbling slowly. Daphnia drop to the bottom and are inactive in the dark.
Rule No. 2. Give them light, 24 hours a day. Daphnia need to be warm and happy to reproduce.
Rule No. 3: Keep them at about 72° F. Use a heater if necessary.
Feeding
Bill feeds his daphnia the following: Mix one package active dry years with one cup soy flour. Once or twice a day stir 1/4 tsp. of this mixture into 1 cup warm water. Pour into the daphnia tank; it will turn cloudy. When the water is clear again, feed the culture again. Overfeeding will cause the culture to crash (die); experience will teach you how much to feed.
“I also keep some large ramshorn snails in the tank, which I feed a lettuce leaf once or twice a week. The snails produce infusoria, which is more food for the daphnia. If you must be gone for a few days, just throw in a couple of lettuce leaves and the bugs won’t starve while you are gone. The snails are also a good indicator of water quality.” When the water is really bad the snails will all go to the top
Harvesting
“Never harvest by just netting out the daphnia. Instead, siphon them into a bucket through a shrimp net, refilling the tank with clean water. The quantity of water to remove depends on the size of your daphnia tank.” About every 10 days, siphon the mulm from the bottom.
You can sort the daphnia by size by pouring them through fish nets of different sizes.
Reference: Childers, Bill. “Raising Daphnia.” Finsanati, newsletter of the Greater Cincinnati Aquarium Society, March-April 1998.
— G.C.K.A. Newsletter, November 2004 Return to top of page
Feeding Daphnia –
Part I – From the Fishroom and other places
Daphnia are a staple food for fish, and one that can be fairly easily cultured by the amateur aquarist, given sufficient space, light, and adequate feeding.
But careful feeding of daphnia is almost an art form.
What to feed these little crustaceans? There are almost as many answers as there are aquarists raising them. Among the many possibilities from the fishroom:
- algal and plankton cultures
- greenwater
Algal and Plankton Cultures
“The key to keeping these [daphnia] cultures going is to feed them every other day with a small quantity of algal culture. Just enough algae is poured into each container to turn the water a light cloudy green,” says Eric Lund.
Biological supply houses sell cultures with instructions for raising daphnia with Euglena and other types of green plankton. However, for raising mass quantities in-house, they use brewer’s yeast. Euglena is safer because it doesn’t use up as much oxygen, but it doesn’t produce the same density or quantity of daphnia.
Green Water
Green water is a great food for daphnia, living and even multiplying until consumed. It is cheap, easily cultured, and hard to overfeed.
“I produce green water in quart jars using soft water with a very small pinch of Miracle Gro and a similar amount of table sugar added,” says Eric Lund. “To get things going I seed the jars with a cloudy light green water that looks a lot like the contents of a severely neglected fish tank. I add a bit of this water to my culture tanks every couple of days when the water in the cultures appears to be clearing.”
“Green water, or bright sunlight combined with fertilizer (urea or dung) is one of the best (and most natural) foods,” points out Karl Johnsen. “You can also use prepared Liquifry foods (mostly made of pureed peas and trace elements).”
“The best I’ve done with greenwater production was when I bubbled CO2 into the water with an airstone, says David Webb. “My water is transparent, but green. The daphnia seem to have plenty to eat, and I’m always harvesting spirogyra out of the tank as well. A little spirogyra with daphnia caught in it is lots of fun for some fish.”
Other Possibilities
“Other things I’ve added [to my daphnia tanks] in the past,” says David Webb, “include fertilizer tablets of the type not recommended by people on the aquatic plants list (because they cause algae outbreaks). I’ve read that Miracle Gro is another good choice, and I’ve also added ammonium sulfate and potassium chlorate directly to the tank in tiny quantities. I’ve also had pleasing results with 1/2-1/4 bag of composted cattle manure from the garden center per 30 gallons of culture water. Well composted horse manure works well too.”
“I raise daphnia fairly successfully in the non-winter months in a 300 gal. Stock tank that I keep in my (very large) back yard,” Barry Cooper said at one point. “I add a little soluble fertilizer to encourage the growth of microalgae. The harvestable quantity varies as the population fluctuates. I harvest them about once or twice a week.”
A research group studying the effects of barley straw on algal growth in a series of man-made ponds “gave me a daphnia supply all year long – I could collect in three minutes more daphnia than I could get home alive,” says Julian Haffegee. “I continually noticed a variation in color and quantity of daphnia, with pools with clear barleyed water giving the reddest and most abundant, and green opaque water giving just a few, often colorless.”
“Snails and Daphnia go together hand in hand (symbiotic relationships),” Karl Johnsen reminds. “The snails’ waste is good food for daphnia food creatures like rotifers. Starved daphnia do not provide good nutrition for fish. Daphnia fed an hour prior to feeding do. Best to think of Crustacea as ‘grocery sacks’ that need to be filled with food to be of use in killie-culture.”
— GCKA Newsletter, April 2003 Return to top of page
Feeding Daphnia
Part II – From the Kitchen
Daphnia are a staple food for fish, one that can be cultured by the amateur aquarist, given sufficient space, light, and adequate feeding.
But what to feed these little crustaceans? Successful feeding of daphnia is almost an art form, and there are almost as many methods as there are aquarists raising them.
Among the many possibilities:
- dog kibble
- hard boiled egg yolk
- flour recipes
- kitchen scraps
- pea soup mix
- powdered milk
- yeast recipes
From the Kitchen –
Dog Kibble – One aquarist’s trick is dry dog kibble, at the rate of about 1 kibble per week, give or take a few days. The kibble sinks and covers the bottom as it dissolves. The snails grow at an amazing rate. The daphnia grow rapidly and are all bright red.
Flour and Soy – “I currently raise daphnia in a little plastic box (less than 2 gal.),” says Andrea Caiola. “I use tap water [and] … feed them with oat flour, just about 1/10 of a tsp. every 2-3 days. I change 50% of the water every month.”
WestSoy Soy Milk – is prepared soy milk in solution. Ingredients are water, soybean meal, and rice bran syrup. Because it’s in solution, when poured into the tank it mixes with the water without forming sediment. You can judge how much food is available to the daphnia by cloudiness of the water.
Soy Flour Recipe – Take one cup of water from the Daphnia tank and put in a blender. Add one multivitamin, 2 tsp. Soy Flour and 1/2 tsp. Spirulina. Blend for 2 minutes. Refrigerate up to one week. To feed: Take a little stock solution and add it to a pint bottle; fill with water from daphnia tank and add a small pinch of yeast. Cover, shake, let sit for 20 min. Shake again. Add to daphnia culture until water is just cloudy.
Kitchen Scraps, Lettuce
Yeast/Lettuce Recipe (from John George): 1 gallon clear plastic bottle, 2 tsp. Sugar, 1/4 to 1/3 of a 1/4 pkt. (7g) Fleischmann’s RapidRise yeast; chopped up lettuce to cover surface (add more lettuce as it decomposes). Cover container in the sun. Keep outside. “It seems to be very rich, so I’m only adding a couple of ounces at one time; not enough to begin to cloud the water.”
“I sometimes put lettuce or vegetable scraps in the blender and turn it into a nice green soup,” reports Harry Kuhman. “The best suggestion I can give … is to try different things…. Sometimes it takes a few days for the full effect [of a new food] to be seen.”
Pea Soup Mix – Jim Langhammer at the Belle Isle Aquarium in Detroit supposedly fed his daphnia commercial pea soup mix 10 parts and Spanish paprika 1 part. Another variation is frozen peas, with a smaller part of carrots, or beets, or spinach, or sweet potato, or broccoli blended with vitamins until liquified.
Some aquarists feed pureed sweet potato alone.
Yeast Recipes
Most aquarists agree, yeast is a good food for daphnia, but the line between using too much and too little is very fine and difficult to manage, so use caution. Yeast does not emulsify well and often much ends up on the bottom of the tank, to rot or be eaten by the snails; the daphnia culture then blossoms, and the water clears. But the next day bacteria have taken over and destroyed the daphnia.
Dry bakers yeast should be soaked in a small amount of water for a few minutes to dissolve, or run through a blender, then enough fed to barely see the bottom of the container. The water should become clear again in 24 hours. Harvest the daphnia, then feed again. Some spirulina can also be added to the daphnia water a few hours before harvesting. This makes daphnia more nutritious and rich in vitamins.
Sprinkling powdered milk to slightly cloud the culture water works better than using yeast, reports one killikeeper, but don’t overfeed powered milk. The odor is best not described.
“I keep daphnia as a culture,” says Tom Grady. He uses rainwater (filtered for a couple of days through charcoal first) in a ten gallon tank, introduces the daphnia to the tank and feeds them yeast (1/8 tsp. of Fleishman’s RapidRise Yeast). He pours a small amount into the tank until the tank is just slightly cloudy. You have to wait for the tank to be completely clear before adding more.
— G.C.K.A. Newsletter, May 2003 Return to top of page
The lowly earthworm is one of nature’s wonders. It lives underground, converts debris to rich soil, and multiples readily. Most of us don’t think of earthworms very much unless we’re looking for fish bait, but as fishkeepers, we know that earthworms are an excellent, highly nutritious, food source.
Earthworms can be fed to fish of all sizes. Larger fish such as adult Blue Gularis will readily take small or coarsely chopped worms. Smaller fish can be fed on finely chopped worms. Fry can take earthworms that have been pureed to a fine slurry in a blender.
You can purchase worms from a bait store, harvest them from your own backyard, or grow your own in a worm bin or compost pile. For those who garden and compost kitchen waste, worms serve a dual purpose. “A pound of worms will process a pound of garbage a day,” says Mary Appelhof, who has based a successful business on promoting and distributing earthworms. Feeding on debris and garbage, worms turn waste into rich, clean “castings” that are ideal as a growing medium or soil additive.
Perhaps the best worms for home composting or live food culturing are red wrigglers (Lumbricus rebellus) or brandling worms (Eisenia fetida). Both are fairly small (3″ or so), multiply readily, and do well in a temperature range of 40-90ºF, reproducing more at 60-70ºF.
Raising Your Own Worms
You’ll need a covered box, of wood, plastic, or Styrofoam. Drill two or more holes at the bottom of the box front, then on the inside firmly attach pieces of fine plastic screen to cover the holes. This allows drainage, but contains the worms.
Fill the container with peat moss. Soak it completely and stir to assure uniform wetness.
Locate the box in a convenient cool, shaded location and place on six bricks – one at each front corner, and two at the back corners, to allow for drainage. If you like, place a pan under the drainage holes to catch runoff water (this is great for plants).
Put your starter culture of worms in the box. Sprinkle a light layer of corn meal on top of the peat moss. This is all the worms will need, but you can add kitchen trimmings and fruit waste for food as well. Before feeding, use a tined garden tool to stir up the peat moss and food left from the previous feeding. Keep the lid closed. Worms like it dark.
In about a month, you should have a well established worm culture, with worms ranging from tiny to fully adult.
The peat moss must be kept damp. Moisten it regularly. Don’t allow it to dry out (the worms will die), but don’t overwater. Don’t allow the box to freeze, or to sit out in the sun. The worms will die.
If a worm culture is working properly, it will not smell, and can be safely kept inside, in a cool closet, or in a cool spot in the garage. If the soil fouls, the culture can be divided and renewed.
Starter worms can be purchased from your local bait and tackle shop (3-4 containers of red worms), or from worm suppliers. “Breeder worms” are selected for size, and will get a new culture started quickly. “Bedrun” worms are mixed sizes but will work equally well.
Box size? The “ideal” size, according to Mary’s article in Organic Gardening (January 1992) should be about 1 foot deep, 2 feet wide, and 3 feet long. She recommends a finely screened lid to keep out fruitflies and other pests and nuisances.
– G.C.K.A. Newsletter, June 2003 Return to top of page
“I would like to report on the success I am having with a new food mix combined with a tank setup that is producing loads of fry without picking eggs, etc.” Monty Lehman wrote in a recent post to Killietalk.
He started with a 10-gallon tank containing seasoned water of less than 30ppm hardness, and a box filter weighed down with marbles and filled with filter floss. He then added two Jiffy 7 peat pellets, a clump of Java Moss, and a layer of floating plants (Salvinia or Water Sprite). After a day, he added a young pair of Aphyosemions.
The fish were fed a slurry containing: Frozen Hikari brand bloodworms, thawed and rinsed; freshly hatched baby brine shrimp; and small amounts of Golden Pearls fish food, very small crumbled food, and freeze-dried Cyclop-eeze. He stirs the mixture, then uses a turkey baster to “feed the slurry mix to all of my tanks once a day.”
Monty changes 70% of the water after 5 days, to keep it from becoming too acid, then again after 10 days. In a couple of weeks he finds that he has to put a nylon stocking over the end of the drainage hose to “keep from sucking up the many fry that have started to appear!”
Every tank he has set up this way has produced large amounts of fry. He’s used the method with a number of Aphyosemion and Fundulopanchax species, among others. “It’s very efficient at producing large numbers of healthy and great looking adults,” he says, and “feeds fry even when you don’t see them!”
– G.C.K.A. Newsletter, March 2006 Return to top of page
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 with less 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 pageFoods …
Enriching Brine Shrimp nauplii
There has been much discussion recently about enriching baby brine shrimp (BBS, or nauplii) to enhance their nutritional value. As they grow, much of a brine shrimp’s body mass converts to chitin, which is indigestible to fish. Feeding the nauplii increases their nutritional value.
Brine shrimp are filter feeders and will eat almost anything, however newly hatched nauplii have no mouths for the first couple of molts, so feeding them right after hatching does little good. Enrich about 24 hours after hatching, then feed to your fish within 48 hours of hatching.
Brine shrimp nauplii reach the instar 2 stage (when they can begin to feed) about 6 hours after hatching, with nutritional enrichment occurring about 16 hours after feeding, dependent on temperature. The enriched BBS can be stored in the refrigerator for up to three days.
Aquaculturists have supplemented live brine shrimp with nutritional components such as vitamins or calcium for years, and there are a number of different formulas on the market, with Selcon the one most commonly seen. But fishkeepers aren’t limited to commercial preparations for brine shrimp supplementation. Many aquarists make their own formulae.
There are lots of things you can use to gut load shrimp nauplii, including fish oil (cod liver oil), vitamins, and some lecithin (as an emulsifier). Simply mix the ingredients in a blender, add to salt water and put in the newly hatched brine shrimp. Agitate this mixture for 12 hours. The baby brine shrimp become HUFA saturated little packets. You can also add Spirulina algae powder to the mix.
“I have used Selcon by American Marine ,” says Bill Vannerson. “Besides the Unsaturated Fatty Acids, it contains vitamins C and B12,” which can also be added to frozen or freeze dried foods.
“For years I have been adding liquid vitamins to brine shrimp about a half hour before they are fed to the fish,” says Al Anderson. More fish survive and they appear to grow faster. Al used has used Marineland vitamins, but now uses Vitakem brand vitamins.
Mach Fukada uses Selcon or Algamac 2000. Both work for enriching artemia nauplii. “It is possible to overdo and kill the batch [of nauplii] if you use too much” enrichment product, he warns, or if you overstock the enrichment container.
Some aquarists have found that a pinch of baker’s yeast and a few drops of liquid vitamin provide an effective supplement to the hatch water for enriching nauplii.
— G.C.K.A. Newsletter – November 2003 Return to top of page
A couple of recipes for
Frozen Fish Food
A number of aquarists, particularly those with large numbers of tanks and/or fish, have long known that a number of recipes exist for making high-quality, good fish foods at home. If you can find a convenient supplier, beef heart is usually fairly inexpensive and makes excellent fish food. is uis so cheep that it really pays to make your own [food].
Here’s how one aquarist makes beef heart food.
- 1# bag of frozen popcorn shrimp
- 1/2 regular bag of frozen green peas.
- 1 jar Gerber’s baby food carrots (made with water)
- 1 tbs. Fleischman’s wheat germ
- 1/2 tsp. liquid bird or reptile vitamins
- 6 oz. quality non-color enhancing flake food (earthworm flakes are great)
- 2 lbs. salmon (fresh is preferable, but canned will do)
- 1 regular can white meat tuna, water packed
- 1 lb. frozen popcorn or frozen cocktail shrimp
- (optional) 1/2 tsp. spirulina powder.
- about 15-20 wingless fruit flies per container
- 8-oz. disposable plastic glasses
- Carolina Biological Supply Formula 4-24 Drosophila medium
- Baby cereal (Gerbers Oatmeal, Pablum Rice, etc.)
- Bread, dampened with water, or milk, or yeast in water
- Cornmeal; for microworms mix with water to a thick slurry
- Oatmeal (regular, cooked); for microworms add some dry when the culture starts to get soupy
- Purina Cat Chow, Trout Chow, Game Chow
- Plain or vanilla yogurt
- Wheat Germ and Oatmeal
- Yeast, mixed into oatmeal; or mixed in water and poured onto whole wheat bread.