Ctenopoma, the African Climbing Perch

By Neale Monks

Order Perciformes, Suborder Anabantoidei, Family Anabantidae

Introduction

The African climbing perches (sometimes referred to as “bush fish”) are labyrinth fish, and so are closely related to the much more familiar gouramis and bettas, which all come from Asia. Although they have never been truly popular, the African climbing perches of the genus Ctenopoma are consistently imported and offered for sale to aquarists with an eye for something a bit different. Like their Asian cousins, Ctenopoma are generally hardy and easy to keep, but there are some things the aquarist needs to take into consideration before introducing some into a community tank. But if you take the time to help them settle into your aquarium, you will quickly find these to be fascinating fishes worthy of a bit of extra effort.

Incidentally, the “C” at the front of Ctenopoma is silent, thus the name is pronounced “teen-o-pomer”.

Description

Most Ctenopoma are laterally compressed fish with large eyes and big mouths. Compared with gouramis, which often have quite short dorsal fins, Ctenopoma have long dorsal fins, and at first glance it’s very easy to think you’re looking at a cichlid rather than a labyrinth fish. But labyrinth fish they are, and if you watch them for long enough, you will eventually see them come up to the surface for a gulp of air. The following are the most commonly seen species and the ones that are best suited to the home aquarium.

Ctenopoma acutirostre

This is one of the most popular species, and in some ways a good species to begin with. It is basically light brown with dark brown spots, and in juveniles especially the contrast between the two colours is vivid enough for these fish to sometimes go by the name of “panther fish” or “leopard fish”. While the colours do become a bit more muted as the fish ages, they remain attractive animals. Ctenopoma acutirostre is very hardy and long-lived, but it is also among the most predatory of all the species, and will not eat dried foods, flakes, or pellets. Live foods, such as earthworms and mealworms will be happily taken; frozen foods, such as bloodworms and mosquito larvae, are also relished. Although fairly big (eventually reaching lengths of 10 to 15 cm in captivity) it is also rather shy and easily bullied. Ideally keep this fish with its own kind or else mix with other peaceful species, such as the larger tetras and barbs, Corydoras catfish, and plecs.

Ctenopoma ansorgii

A very pretty species that is well suited to a quiet aquarium, this fish rather resembles Badis badis is appearance and habits. It is small, growing to around 7 cm in length, and feeds almost exclusively on insect larvae such as bloodworms. Unfortunately, like most other Ctenopoma, it will rarely take flake foods, and being a very slow moving fish cannot compete with more active species at feeding time. So while it will work well with bottom feeders like Corydoras and kuhli loaches, and fish that stay at the top, like hatchet fish and killifish, it is probably not a good idea to keep these fish with boisterous midwater species. The selling point to this fish is its impressive ability to change colours, and males especially don a stunning livery of red and greenish-black vertical stripes during the breeding season.

Ctenopoma kingsleyi

A hardy, but rather drab species that looks and behaves just like the Asian climbing perch Anabas testudineus. Basically green or grey with a lighter belly and some white edging to the fins, it is stockier and less laterally compressed that most of the other species in the genus. Ctenopoma kingsleyi is rather large (up to 25 cm in length) to make a good aquarium fish, but is nonetheless quite commonly seen in tropical fish stores. Potentially a good companion for large but peaceful catfish, silver dollars, and tinfoil barbs in a jumbo-sized community tank, it is a bit timid and is easily bullied by the more aggressive cichlids. Unlike many other Ctenopoma, this species can be weaned onto flakes and pellets, though this may take some time.

Ctenopoma nanum

Similar in size to Ctenopoma ansorgii, this is one of the few climbing perches that regularly do well in ordinary community tanks. Although like the other species it is predatory, its size means that it only poses a risk to very small fishes, such as livebearer fry. Though lacking the gaudy colours of Ctenopoma ansorgii, it is attractively marked, with vertical light and dark bands that become especially bold during breeding. This species has been moved (along with several others) to a distinct genus, Microctenopoma, and thus it is possible that some retailers may label these fish up Microctenopoma nanum.

Ctenopoma fasciolatum

This middle-sized Ctenopoma is another species that is more correctly referred to the genus Microctenopoma. It is a tolerant, hardy fish that does well in the right community tank, and doesn’t hide much, unlike most of the other Ctenopoma, and readily adapts to a mixed diet of dried and frozen foods. Essentially a metallic blue with silvery speckles, this fish is remarkable for its ability to change colour, becoming much lighter or darker as the mood takes it. Another species, Ctenopoma congicum, is very similar except being more reddish-brown than blue.

Behaviour

All Ctenopoma are relatively shy compared with gouramis, and they will only do well in a quiet aquarium. Once settled in, they do become bolder and much more fun, but at least initially do not be surprised if your new fish hide most of the time. Decorating the tank properly will go a long way to making your Ctenopoma feel more at ease: provide plenty of caves, and use real or plastic plants to create lots of shade. Although not actually nocturnal, these are not fishes of the open water, and in the wild they rarely stray far from vegetation. The more densely planted the aquarium, the more at home the fish will feel, and the more quickly they will settle in. Consider adding some blackwater extract to the water; this will dim the lighting a little, making the fish feel more secure even in the open parts of the tank.

Generally speaking, Ctenopoma are tolerant of one another, though males do become territorial when breeding. Provided the tank is big enough and each fish has a cave to call its own, these fish are much less timid when kept in small groups than singly. While not as gaudy as gouramis or cichlids, they do not dig and they do not go out of their way to start fights, so they can be relied on to behave nicely in communities of fish of comparable size.

Aquarium requirements

Since these fish do not swim much, an aquarium for Ctenopoma does not need to be especially large; the smaller species like Ctenopoma ansorgii will do well in tanks from about 60 cm in length, while big species like Ctenopoma acutirostre will need something from 90 cm upwards. Although they do breathe air, only a few are as adapted to stagnant water as the Asian gouramis and bettas, and so on the whole it is best to provide water that is well filtered and oxygenated.

Feeding can be problematical: several species, including Ctenopoma acutirostre and Ctenopoma ansorgii rarely take anything other than live foods or frozen substitutes. Do not assume that your African climbing perch will adapt to dried foods, flakes, or pellets; some do, but not all.

As these are African fish, they make ideal companions for many of the other interesting fish from that continent. The smaller species work very well with tetras such as the Congo tetra and the “African glowlight” Nannaethiops unitaeniatus. The larger species are best kept with slightly bigger fish, such as ropefish, the smaller species of Polypterus, and the butterfly fish Pantodon bucholzi. Upside down catfish are superb companions for these fish, provided that they do not need to compete for hiding places, and likewise mormyrids such as the elephant nose Gnathonemus petersi can work well. Cichlids are an option, but avoid aggressive species: kribensis and Egyptian mouthbrooders might be the right size to keep with Ctenopoma ansorgii and Ctenopoma nanum but they may end up terrorising the poor Ctenopoma. Likewise, tilapia and jewel cichlids would not make good companions for the larger species like Ctenopoma acutirostre.

Breeding

Telling the sexes apart outside of the breeding season is difficult, when male Ctenopoma ansorgii and Ctenopoma nanum at least can be relied on to have the brighter colours. Male Ctenopoma fasciolatum often have elongated tips at the ends of the anal and dorsal fins, and so aren’t too tricky to distinguish. Ctenopoma acutirostre and Ctenopoma kingsleyi are much more challenging, with about the only regular characteristic that the aquarist can observe being the patches of spines males have on the head and body. Note though that both sexes have spines on the gill covers.

While Ctenopoma will adapt to hard water if they must, breeding requires soft and acid water conditions. Ctenopoma build bubble nests and then the male looks after the eggs, but largely ignore the fry. Once the eggs hatch, the fry will take infusoria at first, and after about a week, brine shrimp nauplii. These fish aren’t bred very often, which is a shame, as species like Ctenopoma ansorgii and Ctenopoma nanum are attractive and desirable fish.

Diseases and disorders

Like most other labyrinth fish, these are robust, hardy fish in most regards. Provided they are in a quiet aquarium where they are not bullied and are able to feed properly, they generally do well. Since the stock offered in retails stores is almost always wild caught, parasitic infections, skin and fin damage, and starvation are all possible problems. A period in a quarantine tank would be a good idea, but failing that, keep a close eye on the fish to make sure they are behaving normally and eating well. Even with those species that will eat flake or pellets, fattening them up a little on live and frozen foods will do no harm at all.

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