ARK - Arizona Rivulin Keepers
The purpose of this guide is to help new killifish hobbyists handle some of the
peculiar conditions that can occur in the Phoenix metropolitan area in
particular, but also throughout much of Arizona. The suggestions are based upon
the experiences of other killifish keepers and we offer these to help you
succeed with this colorful group of fish.
Keeping Killies in Arizonaby Allan Semeit
CHAPTER 1 - It's The Water
One of the keys to successfully keeping and breeding aquarium fishes is
providing quality water conditions. While most aquarium fishes will adapt to
your local water and live quite well, others may require some adjustments.
Still others may require major changes before they will thrive and/or breed. In
many cases, this means attempting to reproduce the natural water characteristics
from where the fish originates. Let us examine some of the important water
quality factors to see how they affect killifish.
Water hardness is used to describe the mineral content of your water. If water
is considered to be hard, that means it has a relatively high mineral content of
elements such as calcium and magnesium. Soft water is relatively free of these
minerals. In the United States we usually measure total hardness in terms of
Parts Per Million or ppm. Europeans use a different measure called a Degree of
(German) Hardness or DH or GH. One degree of DH equals 17 ppm. There is no
uniformly accepted standard so you will find both measurements used. Below is a
rough division of hardness:
Parts Per Million:
ppm 0-50 - very soft
51-100 - moderately soft
101-150 - moderately hard
151-300 - hard
above 301 - very hard
Phoenix area water is very hard. It measures somewhere around 350-400 ppm of
Total Hardness. This varies somewhat throughout the year, as well as from
community to community. Knowing your approximate hardness can be important to
successfully keeping killifish.
Since many of the popular killies originate in tropical rainforests with very
soft water, many killie hobbyists try to replicate those water conditions. Most
killie-keepers would say that a hardness of 50-150 ppm is about right for
rainforest killies. Considering that our local water is three or four or more
times harder, it is perhaps surprising that many of the rainforest species will
thrive and breed in our tap water. You will find that most do just fine in
Phoenix water. In fact, there are actually some advantages to maintaining
rainforest killies in hard water. Colonel Joergen Scheel, one of the patron
saints of killie-keeping, advocated using harder water. One of the reasons was
that the pathogens (diseases, etc.) that affect soft water killies generally do
not thrive in hard water. Another is that harder water is more stable
(buffered) and is less likely to suddenly become hyper-acidic.
While most killies will adapt to Phoenix water conditions, you may encounter a
few species of rainforest killifish, especially those that are wild imports, or
those bred and raised in very soft water conditions, that do not prosper in
regular Phoenix water conditions. Many South American annuals appear to belong
to this category too. There are several ways to handle this:
1. You can add a peat (black-water) extract to the aquarium water. Peat is a
natural material that tends to soften water and add beneficial organic compounds
2a. You can gradually reduce the hardness by mixing in distilled or reverse
osmosis (RO) water. Do not use pure distilled or reverse osmosis water. Your
fish require some minerals in their water. That is why you blend in these with
your tap water. Always be sure to SLOWLY adapt your fish to softer water. A
rapid change in osmotic pressure can burst the gills and kill your fish.
2b. As a rule, do not use "softened" water. Water that goes through a water
softener has the calcium and magnesium ions replaced with sodium ions. While
this does lower the Total Hardness, often dramatically, the resulting water has
an extremely high sodium content that can be detrimental to some fishes, their
egg development and the growth of plants. Allan Semeit reported that "softened"
water coming out of his kitchen tap measured 523-5 Total Dissolved Solids (TDS -
see below) and 1 DH (17 ppm) compared to 492-3 TDS and 22 DH (374 ppm) from the
unsoftened water from his front outside faucet.
3. Finally, if a species does poorly for you, despite providing "ideal
conditions" trade them. You might have an incompatible pair. You might have
any number of things that are affecting them. Let someone else have the
opportunity to keep and breed them. Also let the new owner know what you have
Before you make any adjustments to your water, you need to know the quality of
your water. One of the easiest ways is to contact your local water department.
Most publish annual reports. Some are also available on-line. These are fairly
general and can cover a large geographical area.
Another option is to purchase test kits and meters. Pool supply stores,
hardware stores (such as HomeDepot) as well as aquarium stores sell kits to
measure your hardness. Chemical reagents have a definite shelf-life, but these
will tell you approximately what your water is like. Even more accurate than
the kits are the electronic meters. There are several types of these. The
first measures hardness only. Another one that is more commonly used by
hobbyists is a meter that measures Total Dissolved Solids (TDS). TDS includes
more than just the calcium/magnesium/sodium ions that we call "hardness." These
extra elements can include other minerals and organics.
In summary, most rainforest killifish will adapt to Phoenix water without any
need to soften it. These include favorites such as Fundulopanchax gardneri,
Aphyosemion australe, and Epiplatys dageti. And don't forget that there are
other killies besides those from the rainforests! Many of these, including the
Lebias (formerly Aphanius) group, as well as most North American killies,
actually prefer our unsoftened tap water.
CHLORAMINE IN YOUR WATER:
Arizona water companies frequently use chloramine to kill bacteria. This
persistent form of chlorine also will kill your fish. There are several methods
of neutralizing or removing chloramine. The old technique of letting water
"age" in a bucket or tub, maybe with an airstone added, does not work with
chloramine, as it can remain potent in the water for a month or more.
The easiest method to remove chloramine from your tap water is to add a liquid
neutralizer such as Kordon's Amquel. Add the recommended amount and the
chloramine is eliminated. As a variation on this, Peter Unmack recommends using
sodium thiosulphate - 111 g in a total of 200 ml solution - one or two drops per
gallon. Peter notes it is an inexpensive alternative and that you can obtain
sodium thiosulfate through photographic developer supply places.
A second option is to pre-filter your water before it goes into a reservoir with
activated carbon or ammonia-removing crystals (for example: White Diamond
Ammonia-Neutralizing Crystals from Marineland or Ammo-Chips from Aquarium
Pharmaceuticals). Perhaps the ideal system has been described by Wright Huntley
from the Bay Area Killifish Association. Wright runs his water through two
carbon blocks. He rigorously tests the water leaving the first carbon block
with a chlorine test kit. When the chloramine eventually punches through the
first filter, he replaces it. The second filter prevents the small amount that
got through the first filter from reaching his reservoir. He turns off the
incoming water, discards the first carbon block, moves the second carbon block
to where the first was, and then installs a new carbon block in the second
filter, before turning the water back on.
A third option is to set up a reservoir and filter the water while it is in the
reservoir. Allan Semeit has adopted this method and uses a large plastic
storage tub that holds about 20 gallons. There is a submersible filter causing
the water to move continuously. The filter contains a mix of activated carbon
and ammonia-removing crystals. There is also a bag of these materials in the
water. Additionally, there are strips of Poly-Filter (an absorbent filter
material) in the tub. All of these materials are periodically replaced with
fresh ones. Besides removing chloramine, these materials absorb harmful
organics, toxic ammonia, heavy metals, phosphates, and help purify the water
What system should you use? That will depend upon what tank or tanks you have,
and how much water you change. As a rule of thumb, most fish, not just
killifish, will benefit from a 10-20% water change (replacement) every week.
Frequent small changes are better than massive ones.
Finally, whichever method you use, you should still "age" water for 24 hours
before adding it to an established aquarium . "Aging" allows the water to warm
to room temperature and lets any excess gases (such as carbon dioxide) to be
released before the water goes into your tank. If you have ever noticed tiny
bubbles on the sides of your aquarium after a water change, those are from
excess gases being released from your water.
Living in the desert where summer daytime temperatures can exceed 110 degrees
Fahrenheit can pose a real challenge to keeping killifish. Typical rainforest
killies live in waters that are fairly constant year-round in temperature. For
most of these, that temperature is about 72 degrees F. The killies found at
higher elevations live in even cooler waters. How then does the hobbyist keep
his killies at these temperatures?
Simply, here in Arizona, it isn't going to happen. At least, not at those
temperatures - unless you want to pay for excessive air-conditioning during the
summer and heating during the winter. However, you can still keep just about
all killies in Arizona if they are maintained at typical room temperatures. For
example, most people keep their house about 80-82 degrees during the summer and
between 68-72 degrees during the winter. Killifish will generally do just fine
at these ambient temperatures and ARK members report keeping a large number of
rainforest killies without any difficulties at these temperatures.
With the gradual change from cool winter temperatures to our warmer summer
temperatures, your killifish will tend to become more active. This applies even
to those killifishes that have habitats that usually remain about 70-72 degrees.
Contrary to what you might expect, many killies of these naturally cool-water
killies breed more actively during the summer. Then when the temperatures drop
closer to their natural range during the winter, these killies actually slow
down and even stop breeding.
You may reside, or keep your fish, in a location that is not well insulated.
Even if your temperatures range above and below those mentioned, you can still
keep killies. There are a number of killies that tolerate, and even enjoy,
higher temperatures. Pupfish, the desert fishes from the Middle East,
Aplocheilus species, some Nothobranchius, and even some South American annuals
prefer water in the 80s, and some can even tolerate it even warmer. Many of
these same species can also tolerate cooler winter temperatures. You may have
fewer choices in these circumstances, but you can still find killies that you
One caution about temperatures - AVOID locating your fish where they might
experience rapid temperature changes. Do not place a tank in a window, or where
the air conditioner/heater blows upon them. Sudden changes can weaken your fish
and cause you to lose them. Gradual changes to the water are almost always
CHAPTER 2 - Housing Your Killies
TANKS AND CONTAINERS:
There are many ways to keep killifish. Because of their great variation in
habitats, not all killies can be handled in the same way. A killifish from a
marine lagoon will have different requirements than one from a mountain stream.
While most killies average about two inches in length, a few can reach six
inches or larger, and some barely exceed an inch. Rather than attempt to cover
all of the possibilities, we will focus on the "typical" killifish. The
"typical" killifish would primarily include genera such as Aphyosemion,
Epiplatys, and Fundulopanchax primarily from west Africa, Aplocheilus from India
and southeast Asia, and Rivulus from central and South America.
The Display Approach
Many hobbyists like to maintain display tanks. In general, killifish do not
thrive in this environment. Most killies tend to be shy and timid when kept
with more boisterous or active tankmates. If you want a large display tank, say
a 26-gallon aquarium, you would probably have better success keeping a group of
the same species of killie. Fundulopanchax gardneri, particularly the N'Sukka
population, would be one good candidate for such a set-up. These are brightly
colored and less shy than most killies. Both males and females of this
population can be housed together.
Another display option, besides the single species aquarium, is a male-only
approach. The absence of females tends to reduce possible male-to-male
aggression. Some male killies seem to have a "rooster" mentality of killing
every potential rival - and the lack of females tends to mute this. This
males-only tank can be single species or contain a number of different killies.
Be sure to provide plenty of hiding places! Since most female killifish can be
difficult or impossible to distinguish by species, don't mix females unless you
are very certain that you can tell them apart.
This leads to another option. You can consider maintaining two very different
looking killies (both males and females). The two species should be of similar
size and temperament. For example, you can successfully keep Epiplatys dageti
and Aphyosemion australe together in a ten-gallon or larger aquarium. Both
species tend to be peaceful and ignore each other. Allan Semeit reports keeping
these two species for several years without problems. He noted that each
species lays eggs that are distinctly different in size so you can tell which is
spawning. He also incubated the eggs of both species together and raised the
fry together as well.
The "Typical" Killifish Set-Up
The small size of killies allows you to maintain them in smaller tanks. Perhaps
the most popular size of killifish aquarium is about two-gallons. This is
usually either a two-gallon glass tank or a "medium" plastic Critter Keeper.
Generally, you can permanently keep 2-4 adults in tanks of this size. The
two-gallon tank is large enough that you can install a small filter (such as a
sponge filter) and the volume of water is sufficient to reduce the chance of a
rapid change of quality or temperature. Because of the relatively small tank
size, killie hobbyists can house a large number of species in separate tanks in
a minimal amount of space. The drawback to two-gallon tanks is their cost. A
glass two-gallon tank or a plastic two-gallon (medium) plastic Critter Keeper
will run about the same price as a ten-gallon aquarium.
As an alternative to two-gallon tanks, some hobbyists prefer to use ten-gallon
tanks. When they need two-gallon set-ups, they make, or obtain, glass
partitions that they silicon-cement into the ten-gallon tank. In this way they
divide the tank into two or three compartments. These compartments also need to
be well covered as most killies are excellent jumpers. The advantages to using
ten-gallon tanks include price and uniformity.
One of the afflictions associated with killie-keeping is having too many fish.
To resolve this problem, killie-keepers use a variety of expedient containers.
The development of plastic shoeboxes, shirtboxes, and the larger sizes has been
a blessing. These containers, with their tight-fitting lids, are excellent for
killies. The larger sizes with their wider surface area are wonderful
"grow-out" tanks for maturing fry. The only draw-back to these types of plastic
containers is their reduced visibility. This type of plastic is harder to see
through than with a glass container or the plastic used in Critter Keepers.
Besides plastic shoe-boxes and sweater boxes, there are a variety of plastic
boxes, jars, or whatever, that can be adapted to house killies. You might be
surprised to discover suitable containers. Consider things like the larger
pretzel and candy jars. If you have a deli nearby, check to see if they use
glass pickle jars. They will usually be glad to have you take them off their
hands. Many of these will hold about two gallons of water and can be recycled
into fish tanks after their initial usage.
Whether you decide to keep killies only for display, or if you decide to breed
them, you will find lots of options in housing these beauties. Again, be sure
to have a tight-fitting cover.
Understanding several terms will help us with a discussion of filters. There
are three general ways filters remove substances from aquarium water. These
Mechanical filtration is the collection of debris and other solids from the
Biological filtration uses helpful bacteria to convert toxic fish wastes to
less harmful compounds.
Chemical filtration absorbs harmful products from the water and may also
release beneficial substances into the water.
When you set up your killies, what is the best type of filter to use? This
answer can really vary. If you have set up a 10-gallon or larger tank, you have
quite a few options. If you are asking about a two-gallon, or smaller, tank,
your choices are more limited. Let's consider some options.
Power outside (hanging) filters:
Generally you want to avoid these. Although they can be excellent
mechanical filters, they also provide an exit point where your fish can jump out
of the tank. Killies are notorious jumpers. These filters are only
suitable for 10-gallon or larger tanks.
Power submersible filters:
These can be very suitable for a killie tank and they serve primarily to
remove debris from the water. Be sure to restrict the flow to a gentle, slow
movement. As a general rule, killies do not like a strong water flow. In
fact, if you are having a problem with some, particularly Nothobranchius
species, try to really restrict the water circulation to a minimum. Power
submersible filters are most suitable for 10-gallon or larger tanks.
These can be very adaptable and are excellent for "permanent" set-ups. The
gravel bed should be about two inches deep and provides biological and
mechanical filtering. These filters should be "hydro-cleaned" (using a siphon
that tumbles the gravel and removes the debris from the gravel) regularly. In
the Phoenix area, air-stems not only build up a calcium deposit, but also
become home to a gooey bacteria that plugs the air flow. Be sure to use
undergravel filters with easy-to-remove and clean air-stems.
Some aquarists use undergravel filters in large "grow-out" and breeding
tanks. Instead of running undergravel filters across the entire bottom and then
covering them with gravel, they keep the bottom bare. As a filter, they
use low, flat, circular goldfish bowls. Inside the bowl they place an round
undergravel filter and cover it with gravel. For breeding purposes, spawning
mops are placed over the gravel. Species like Blue Gularis lay their eggs in
These are probably the most popular filters in smaller set-ups. Like
undergravel filters, sponge filters provide biological and mechanical
filtration. The sponge provides a "nursery" for micro-organisms known as
infusoria and these can be an excellent first food for newly hatched killie fry.
The drawbacks to sponge filters are again clogging air-stems and the
danger of trapping fish under the filter (some killie-keepers silicon-cement
marbles under the filter to keep it raised). These are best used in bare
bottom breeder tanks from two-gallons to maybe ten-gallons.
These are an old aquarium stand-by - and they still work. The filter
materials can be lava rock, gravel, sponge, filter wool (or floss), activated
carbon, ammonia-neutralizing crystals, or any combination of these (as well
as some others less commonly used). While primarily used to
mechanically filter the water, box filters can also provide chemical and
biological filtering. Box filters offer flexibility through a choice of
materials. They also tend to be bulky and somewhat of a visional
eyesore. Air-stem clogging is also a problem. These are most suitable for
two-gallon to maybe ten-gallon tanks.
CHAPTER 3 - Good Beginning Killies
What is available -
Finding killifish can be a real challenge. If you check your local tropical
fish store, you will occasionally find a few killies. However, it is the rare
store that has any selection. The most commonly available killies are:
1. The American Flag Fish (Jordanella floridea): is a native of Florida and is
an unusual killie that will sometimes act like a cichlid, defending territory or
a spawning site. The Flag Fish is a very attractively colored fish that is
somewhat chunky and can reach four inches. This very hardy species requires at
least a 10-gallon tank and, in Arizona, will thrive in a large pond.
2. The Blue-fin Killie (Lucania goodei): another Florida native, but one that
is seldom intentionally purchased by an aquarium store. This species often
accompanies plant shipments from Florida (as eggs) or can be found as part of a
Ghost Shrimp shipment. This is a slender, peaceful killie that reaches about 1
1/2 inches. The Blue-fin Killie tends to be very plain in store tanks, partly
due to being young fish. Color is variable throughout its range and some
locales can produce stunning fish.
3. The Golden Wonder Killie (Aplocheilus lineatus): is a golden color morph of
a killifish native to India. Lineatus can grow to 5 inches. They have a
pike-like shape and are surface-dwelling fish. They are best kept at
temperatures in the high 70 or low 80 degrees Fahrenheit with other
similar-sized aquarium fish.
All three of the above species are fairly easy to keep and can make nice
additions to your collection of fish.
Where do I find other killies?
The above three species barely scratch the top of the iceberg as far as
killifish go. Many hobbyists will see pictures of gorgeous killies in aquarium
magazines and books and wonder where to obtain them. There are a number of
First, you will want to find out if there is a local aquarium society in or
near your town. In Phoenix, you have both a general aquarium club, the Dry
Wash Aquarium Society, and a club specializing in killifish, the Arizona
Rivulin Keepers. Local breeders are your best source of both killies and
information on how to succeed with them.
If this is not an option, then check out the American Killifish Association
at http://www.aka.org. AKA members receive a monthly bulletin with a list of
people buying and selling killies. All listers agree to abide by the AKA
Code of Ethics.
A third source is checking for killies on-line. You will find individuals
who offer killies through their personal websites. You will also discover
commercial sites such as AquaBid where you can participate in auctions. With
these sources, let the buyer beware...
What killies should I first obtain?
There are a number of killifish that are considered to be excellent beginner
killies. The list below is not intended to be complete, but rather provide some
1. The Gardneri Killie (Fundulopanchax gardneri): is actually a large complex
of closely related sub-species, found mostly in Nigeria. Most are fairly easy
to keep and breed. Perhaps the easiest Gardneri is the population from N'Sukka
(or Nsukka). All Gardneri grow to a little over two inches and live three to
five years. Some are feisty; others like N'Sukka tend to be relatively
peaceful. Gardneri tend live near the bottom to the mid-water level, are eager
feeders and will accept most foods, including flakes. Most Gardneri are
bottom-spawners that prefer to lay eggs in bottom mops, plants like Java Moss,
or in a substrate (gravel or peat). The notable exception to this is the N'sukka
population. They seem to like to lay their eggs near the top of a floating mop.
Gardneri eggs require about two weeks to incubate. Several populations,
Rayfield and Jos Plateau, may be better incubated in a plastic bag in damp peat
over a three week period.
2. The Firethroat Flattop (Epiplatys dageti): is a two-inch pike-like killie
with vertical bars from Liberia in western Africa. Males develop an orange-red
throat and have an extension on the bottom of their tail - a sort of mini-sword.
This is a very peaceful top-dwelling fish that accepts most foods and lives
three or more years. Dageti (pronounced Duh Jay EYE) will lay eggs from the top
to the bottom of a floating mop. The eggs hatch in about two weeks. The adults
do not predate their eggs but will eat the fry. The only drawback to keeping
Dageti is that you tend to produce more females than males.
3. The Chocolate (or Golden) Lyretail (Aphyosemion australe): is native to the
coastal rainforests of Gabon and perhaps the Congo. This species has been a
long-time aquarium favorite and is available in several color morphs, as well as
recent wild collections. Body colors can range from a rich chocolate to orange
to reddish. Maximum size is a little over two inches and their lifespan
averages 3-5 years. Males can develop attractive extensions to the top and
bottom of their tail fins. The Lyretail is usually a very peaceful killifish,
generally inhabiting the lower and middle levels of an aquarium. They will
accept most foods. They lay eggs in plants or mops and the eggs incubate in
about two weeks. Some strains of the Lyretail are easy to breed; others can be
very difficult. Whenever possible, check with the breeder to find out how they
4. The Two-striped Killie (Aphyosemion bivittatum): is another long-time
favorite. This is actually not one species but a large group (called
Chromaphyosemion) of related species where there have been a number of recent
name changes. The group includes Bivittatum, Bitaenitiatum, Loennbergii,
Splendopleure, Riggenbachi, Poliaki, Lugens, and several undescribed species.
Bivs and Bits, as they are called, tend to be surface-dwelling killies that grow
to about two inches and live from 3-5 years. The dorsal and anal fins of the
males of some populations develop long extensions. Bivs and Bits spawn in
plants or floating mops. The eggs hatch in about two weeks. Some of the more
popular locations, such as Aphyosemion bitaenitiatum "Ijebu Ode", are easily
breed in Phoenix water. Others, such as Riggenbachi, appear to require softer
water just to be kept alive, much less spawned.
5. The Guentheri Notho (Nothobranchius guentheri): differs from the above
recommendations because it is an Annual killifish. In nature, this species
lives where the waterholes dry out. Guentheri lays their eggs in the soil at
the bottom of the ponds where they incubate during the dry season. When the
rains come and the waterholes fill, the eggs hatch and a new generation repeats
the cycle. Guentheri are found in Tanzania in east Africa and grow to about two
inches. Whereas the previous four suggested fish are cylinderical in shape,
Nothos are deeper bodied. In the aquarium, they can live beyond their natural
lifespan. A frequent recommendation is to add a teaspoon of salt per gallon as
a Velvet (a disease) preventative. Most aquarists breed Guentheri in a bare
tank with a container with some peat in it. The peat is removed every one-two
weeks, partially dried, and stored in a plastic bag (ziplock works well) for
two-three months. Upon adding water to the peat, the eggs hatch out.