A Fish with "Piscinality": Fundulopanchax gardneri

Author: Mike Hellweg

An aquarist who has kept nearly every kind of fish in the freshwater hobby discusses the killies he describes as having “piscinality”: the gardneri group, beautiful killifish that will appeal to a wide range of fishkeepers.

Piscinality Explained

Over the years, I've worked with many species of killies from all around the world, but I keep finding myself drawn back to the very colorful group of killies from Cameroon and Nigeria known as the “gardneri group.” There just aren't many other killies that can compare in terms of color, variation in challenge from beginner to expert, and overall just being enjoyable to keep. Above all, they exhibit a fun “piscinality” (pronounced pie-scene-al-it-ee)—a new word I’ve coined, meaning “personality.” They are always out in the open, begging for food every time you walk by the tank and displaying for one another under the bright lights. The only drawback to these beautiful fish is that they are so darn hard to find. Most shops don't even try to stock them. The few that do stock them find that they sell very slowly. I'm not sure why. Most colorful fish almost fly out the door!

Why Are Killies so Hard to Find?

Perhaps part of this phenomenon is the name “killie.” I've heard many new hobbyists confess that this name inspires a bit of trepidation. After all, it has the word “kill” right in it. And we killie nuts usually keep them isolated from other fish. That must be because they are so aggressive, right?

Just to clear this up, “killie” is a shortened version of the name “killifish,” which is based on the Dutch word “kill,” which refers to a small stream or body of water (a.k.a. creek) such as the ones that most killies are found in. Hence “killifish” are simply fish from small streams or creeks. Of course calling them “creekies” probably wouldn't help, either. In any case, they are not homicidal fish. To improve their image, I think we should go back to calling them panchax, as they were known back in the early days of the hobby.

The Killie Enthusiast

Killie hobbyists as a rule are very generous with their fish and with information. They have a well-earned reputation for giving away pairs to any new hobbyist who shows even the remotest interest in killies, so it isn't likely that killie nuts themselves are scaring people away.

Killie enthusiasts often keep their fish in a manner that appears strange to the casual observer or new hobbyist. That is, they are notorious for keeping them in small, dark tanks. To them, “plants” often means a pile of acrylic spawning mops. In fact, most of the killies that lay their eggs among the plants in the wild are called “mop spawners” by killie hobbyists. I've been in a lot of water where “mop spawning” killies are found, and I've yet to see a single mop!

“Lighting” usually means a flashlight to a killie enthusiast. “Aquarium” or “tank” means any small container with a tight-fitting lid that can hold water. These can be jars, plastic storage boxes, disposable food containers, fish bowls, critter tanks, or small aquaria. I often find myself in other killie hobbyists' fishrooms on my hands and knees peering into critter keepers with a flashlight to catch a glimpse of their absolutely stunning killies. I think this practice is one of the main reasons many new hobbyists shy away from the killie hobby. They want to see their fish, not hide them away on a bottom shelf! I will note right here that these types of tanks are not necessary for successful killie maintenance. You can enjoy your killies, especially members of the F. gardneri group, right out in the open in a normal aquarium. It’s just that with most killie hobbyists, function wins out over form, and small tanks with dim light and piles of mops work.

A Brief History of Killies

Fundulus gardneri was first described in 1911 by the Belgian zoologist George A. Boulenger. He named the species in honor of the first person to collect it, a gentleman named R. D. Gardner who reportedly collected them at Okwoga on a small tributary of the Cross River in Nigeria. They were first imported for the hobby beginning in 1913, and they have been available in specialist circles almost continuously ever since, though even today, hobbyists still travel to Nigeria, and more so Cameroon, to collect wild ones.

These killies are found in forest streams and in small streams out in the open savanna. Usually, they are the only Fundulopanchax species found in their particular stream. This is a bit unusual, as with many other killie species, a couple to several species from a single genus can be found together in the same area. For the most part, they are found in extremely shallow flowing water, but in at least one case (F. gardneri lacustris) they are found in a lake. Like many killies, they are often found in water merely an inch deep, and are reputed to be able to move from puddle to puddle by flipping or crawling. This means that jumping is a natural part of their behavioral repertoire. Keep their tank tightly covered! They can get through even a very tiny opening.

For a while, they were known as Aphyosemion gardneri, and in many texts, that is how you will still find them listed. The subgenus Fundulopanchax was elevated to full generic status and separated out of Aphyosemion about 40 years ago, and recent studies have confirmed that this is a valid separation. So currently they are known as Fundulopanchax gardneri, with the subspecies and location name usually following. Recently, Glen Collier has suggested that due to DNA differences, several of the subspecies should be re-evaluated and possibly elevated to specific status, but a quick look at the California Academy of Sciences database shows that as of this writing, no one has made that re-evaluation and all are still considered subspecies.

Killies – A Varied Species

There are currently six recognized subspecies, each with one to several locality variants available in the hobby. Plus, at least one hobby-developed strain and a mystery strain are currently making the rounds.

The males have tremendous variation in coloration, but the pattern is remarkably stable throughout. Most males have colorful edging in either red or yellow on the outer rays of their caudal fin, which develops into a beautiful lyretail as the fish grow. They have bright-red spots on their flanks, and usually the same outer edging on their caudal is repeated in the dorsal and anal fin. Most will reach 3 inches (7.5 cm), and specimens of a few variants have been reported to reach nearly 4 inches (10 cm).

Females are a bit smaller and have an overall olive to tan body color with a few red spots. It is best not to mix strains together, as they will freely interbreed, and females are similar enough that it is difficult to differentiate them from one another.

·         F. gardneri gardneri has several variants, with those from Lafia and Nsukka currently commonly available in aquarium circles. In my opinion, the Lafia variant is far and away the most spectacular of all these beautiful fish.

·         F. gardneri nigerianus is the most widespread subspecies, with several locality variants commonly available including Misaje (which is also available in a domestic albino form), Biassa, Jos Plateau, Makurdi (often listed as Makurdi “red”), Bassua, and Udi Mountain. Most authors have suggested that this be considered a full species—F. nigerianus—while others suggest that all of the F. gardneri gardneri and F. g. nigerianus should simply be considered F. gardneri.

·         F. gardneri clauseni has one common variant from Akure with two color morphs, yellow and blue. These occur together, though hobbyists often separate them out. Some authors now consider this a full species: F. clauseni.

·         F. gardneri lacustris has one variant from Lake Ejagham. Some authors now consider this a full species: F. lacustris.

·         F. gardneri mamfensis has one variant from Mamfe. Some authors now consider this a full species: F. mamfensis.

·         F. gardneri obuduensis has one variant from Obudu. As far as I’m aware, this subspecies has not yet been closely studied. It, too, is sometimes considered a separate species.

There is a mystery variety called F. gardneri nigerianus Innidere that is currently making the rounds and is even available occasionally in better fish stores. It reportedly comes from Oyo State in western Nigeria, but a quick look at a high-resolution map of Oyo State does not show the name. Is it a very tiny village or a tiny stream? I can’t say, and apparently neither can anyone else. Adding more to the confusion, there are two very different fish going around as Innidere! All I can say for sure is that they are stunning fish that make excellent ambassadors for the killie hobby. They are easy to keep and breed, colorful, relatively small at just under 3 inches (7.5 cm), and outgoing, spending their time at the front of the tank, begging for food. They will eat pellet, flake, frozen, and live foods.

Finding the Right Home for Your Killies

Even though many killie hobbyists keep their fish in small, dark tanks, I like to see my fish. And I like to share their beauty with other hobbyists. I keep my F. gardneri in 10-gallon (38-liter) or larger tanks and right at eye-level so I can see and enjoy them whenever I'm in the fishroom. The tanks are well planted, tightly covered, and brightly lit. Even though some hobbyists report that at least some variants of F. gardneri spend most of their time hiding, in my experience with several of the commonly available variants, they don’t shy away from the light. They're always out front and center, begging for food and attention and putting on a show just like an oscar.

Fortunately, most of the F. gardneri variants are very sociable with their keepers. They come to recognize them as the source of food and new water. They beg for food when I'm working around their tank and get all excited when I'm doing a water change, swimming into the current of new water just like danios!

These days, there are many hobbyists with beautiful planted setups in those “plug and play” 10- to 20-gallon (38- to 76-liter) tanks that are available in every shop. F. gardneri seems to be tailor-made for these tanks. So even if you only have one tank and aren't interested in spawning your fish, they make a perfect addition to the peaceful community tank. Males do sometimes spar with one another, but the most damage I've seen is a torn fin. I’ve kept them with tetras, barbs, danios, cories, plecos, dwarf cichlids, and even livebearers with no problems.

Feeding Killies

F. gardneri is a micro predator, feeding primarily on insects and crustaceans in the wild. Fortunately, they are good eaters and even wild-caught fish will take high-quality flake, pellet, frozen, freeze-dried, and live foods in captivity. The flakes and pellets should be designed for carnivorous fishes. I usually feed my fish once a day with a high-quality flake, but when I'm trying to get them to breed, I switch to feeding live foods. I've never been able to get F. gardneri to spawn on just a diet of prepared foods, so I believe there is something in various live critters that is needed to stimulate either sperm or egg production. I feed live brine shrimp (newly hatched and adult), daphnia, fruit flies, flour beetles, Grindal worms, blackworms, and white worms. Occasionally, I'll also add chopped up earthworms and juvenile cherry shrimp. Feeding them with live foods for a week or two before spawning is usually enough.

Newly hatched gardneri are large enough to take newly hatched Utah-strain brine shrimp nauplii right away, which is great because they are relatively inexpensive and easy to find. I feed my young gardneri twice a day, once with newly hatched brine shrimp and once with microworms (any of the available varieties—microworms, Walter worms, potato worms, banana worms, etc.—will work just fine). I'll feed these foods exclusively for the first month and then start adding finely crushed flakes with one of the feedings, eventually working over to one feeding of flake and one of live foods. I continue this feeding regimen until they are ready to breed. At that time, I'll cut down to one feeding a day except when I'm getting them ready for spawning.

Water Parameters

As you might guess from their wide distribution in the wild, F. gardneri are not too picky about water parameters as long as extremes are avoided. They will thrive at a pH between 6.0 and 7.4, with total hardness from almost zero up to 300 ppm. For breeding, it is best to keep these in the middle, with a pH of 6.5–7.0 and a total hardness around 100–125 ppm. Exact numbers are unimportant. The same goes for water temperature. They prefer cooler water in the upper 60s to lower 70s Fahrenheit (upper-teens to lower 20s Celsius), so no heater is needed as long as the room temperature will not go below about 64° Fahrenheit.

Filtration is optional, but water cleanliness is important. If you maintain your gardneri in a smaller tank (5 gallons [16 liters] or less), you don't necessarily need a filter or aeration, but you need to change a large percentage of the water every few days to keep dissolved pollutants low. A sponge filter is more than adequate for a 5- to 10-gallon (16- to 38-liter) tank, providing plenty of filtration and some aeration at the same time.


In the wild, F. gardneri are continuous spawners in places where rainfall is high and water levels are constant throughout the year. In other areas, they are almost what could be considered annual spawners. They lay eggs in the mud that withstand a short dry period, during which the water level may drop, and then hatch when the rains return and the water level rises again. In our aquaria, most variants are continuous spawners, spawning almost every day.

Most killie hobbyists consider them to be variable spawners, laying their eggs in floating or sinking mops, on the substrate, among fine-leaved plants, or even on the filter. Some of the more northerly species are reputed to be quite challenging, but I have not yet found any of the F. gardneri that I've worked with to be more than a moderate challenge.

The male can be a bit hard on the female, so it is generally recommended to have two females to every male. Surprisingly, you often get fewer eggs with this ratio than with a single pair. The reason for this became apparent after watching one of Atlanta-area hobbyist David Ramsey's spawning videos. While the male spawns with one female, the other dashes in and eats the newly laid eggs! After seeing this a few years ago, I began using a single pair and found that I have much better levels of production.

Over the years I have tried all the recommended methods of getting the adults to spawn and handling the resultant eggs. I have even had F. gardneri nigerianus Udi Mountain spawn successfully in a quarantine tank with nothing but a layer of 1- to 2-mm gravel and a sponge filter.

My preferred method for promoting spawning is to set up a 10-gallon (38-liter) tank with a small sponge filter or mattenfilter, a large clump of Java moss (Taxiphyllum sp.) on the bottom attached to a rock, a large area of the surface covered with water sprite (Ceratopteris sp.) or hornwort (Ceratophyllum sp.), and several potted Cryptocoryne in the tank. Make sure there are no snails or shrimp, as many snail species and some shrimp species are not above a caviar snack. I have a layer of sand or fine (1- to 2-mm) quartz gravel about an inch deep on the bottom. The tank is brightly lit. I add a pair, feed live foods for a couple of weeks, and then remove the pair at about day 14. Usually, in a few days I'll start seeing fry darting around the tank. At this time, I start adding newly hatched brine shrimp and microworms (as described earlier).

This method doesn't produce a large number of fry, but you can reliably get a couple dozen each time you do it. This is more than enough to distribute to friends, keep your population going, and maybe even trade for food or supplies if your local shop is daring enough to want to try killies!

F. gardneri is a beautiful killie that is easy to keep and feed, and some variants can be hard enough to breed that even jaded hobbyists will find it a fun challenge. Pictures don’t do justice to these fish. You have to see them in person. Once you do, I'm sure that you’ll want to keep them over and over again—like I do.

See the full article on TFH Digital http://www.tfhdigital.com/tfh/june_2014#pg55