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Related FAQs: Genera Ctenopoma & Microctenopoma, Anabantoids/Gouramis & Relatives FAQs 2, Gourami Identification, Gourami Behavior, Gourami Compatibility, Gourami Selection, Gourami Systems, Gourami Feeding, Gourami Disease, Gourami Reproduction,


Related Articles: Ctenopoma acutirostre by Adam Jackson, Anabantoids/Gouramis & RelativesBetta splendens/Siamese Fighting Fish, Freshwater Fishes

Anabantoids of the Genera

Ctenopoma and Microctenopoma

by: Robert J. Goldstein

Ctenopoma acutirostre

Until 1995, all the "bushfish" were in the genus Ctenopoma. In that year, the ichthyologist Norris described a new species in the quarterly journal Ichthyological Explorations in Freshwater (http://www.pfeil-verlag.de/04biol/e9902d6.html) and found that the genus Ctenopoma consisted of two distinctive evolutionary lines. And so he divided the group into species within either the new genus Microctenopoma and those left in Ctenopoma.

Aquarists have mistaken the size of the fish as a guide to the genus. Hence, many aquarists write about "Microctenopoma" ansorgii, but that fish is in Ctenopoma. A quite similar species (not as brightly colored) is Microctenopoma nana, and the similarly might have led people to draw the incorrect conclusion. Anyway, the "micro" refers to structures on the fish rather than adult fish size.

Is this important? It is for ichthyologists, and some day it may be to aquarists, but for now the importance is that you need both names to search the web (I mostly use www.google.com). Perhaps this evolutionary information may predict how eggs or fry develop, where unknown new species might occur, or offer clues to inducing breeding of these fishes. We could use any clues we can get!!

Breeding remains a mystery. Many of us have bred ctenopomas (I'll use the term to encompass both genera), but we don't know why they bred, and we have trouble getting them to do it again. Ctenopomas breed when they feel like it (which isn't often), and under many different conditions. Just when we've patted ourselves on the back for accomplishing a remarkable feat, we find we can't repeat our successes, so maybe we're not such hotshots after all.

Why so few successes over all? First, ctenopomas are uncommon, so few aquarists even try them, and that leaves little experience upon which the rest of us can rely. Occasionally they're imported and you'll find them at pet shops, but here they usually languish unsold until a serious (or well-heeled) aquarist comes along. If you're that guy, buy the tank, since you may not see that species again. Don't rely on the old statistical model of six fish giving you a 98 percent shot at a pair. Ctenopomas may be imported (or produced) with skewed sex ratios of mostly one sex or another, so get all you can and hope you have both sexes. If you later can identify a pair, that's the time to unload your excess stock at the local aquarium society.

(You're not a member of a local society? That's one of your best sources of rare fish.)

You should also prowl the show tanks of fish stores in other cities. Often larger breeder size ctenopomas are brought in by local aquarists who've decided they had grown too big for their tanks.

Search anabantoid forums on the web, particularly links from the IBC (http://www.ibc-smp.org/refs.html) and the IAA (http://aquaworld.netfirms.com/phpBB2). Follow the links to sellers, or post a query and you'll find suppliers willing

to share their bounty.

Most anabantoids are Asian fishes. But ctenopomas are African. (How the anabantoids spread from one part of the world to the other hasn't yet been figured out, but it must have happened before Tom Ridge started strip-searching funny looking air passengers.) Most produce weak bubblenests to support floating eggs, but some species need the stickiness of many densely packed bubbles because the eggs are heavier than water.

Ctenopomas occur in rivers and lakes of east, west, and central Africa. Some occupy only one river basin near the coast, while others occur in several (usually adjacent) river basins, apparently spreading to adjacent basins that were historically separated by low ridges, and spread into adjacent basins during eons of massive rainfall and flooding. Southernmost Africa is temperate (like the US), and has the related genus Sandelia, ugly fish that lay eggs on the bottom.

Which are the prettiest and most desirable ctenopomas? Of the species you are most likely to find, I vote for Ctenopoma ansorgii (which I've bred) and Ctenopoma acutirostre. The first is small (less than 3 inches) with beautiful orange and dark vertical banding on the body and fins, and the other much larger with black polka dots (or maybe they're waltz dots?) on an iridescent yellow-green body. I currently have a 55 full of excess C. acutirostre given me by Sallie Boggs, after her fish (unexpectedly) spawned and rewarded her with babies by the thousands.

All ctenopomas are slow, lazy ambush predators, so maybe we should call them ambushfish instead of bushfish. They wait among plants, beneath sunken wood, or near rock caves, and shoot their protrusible jaws the short distances to any small prey within range. They are size selective feeders. I put lots of feeder guppies with my C. acutirostre, who proceeded to eat all the males and leave the females.

I find it impossible to sex any of them, so if you get the chance, get several and house them together. They do poorly in polluted tanks, so although you should feed them heavily with live or frozen food, feed them only occasionally and don't take chances by adding dry foods to the tank (which often is left over and rots). They are usually comfortable and color up best with dense vegetation, but even open water species should have clusters of plants and driftwood for hiding niches. Water quality should be rich in oxygen (plants, light aeration), and pH neutral to low. Species from soft, acidic blackwater habitats have excellent color in blackwater tanks, but that doesn't mean they are any more likely to breed. Several ctenopomas come from moderately fast moving, high gradient, rocky bottom and boulder-strewn rivers, but even they typically occur in quieter backwaters, coves, and in undercut banks among plants and tree roots.

Don't count on seeing a bubblenest. These fish are not consistent. Some individual males make a hefty betta-like nest, and others barely spit a few bubbles. With dense vegetation, if the fish breed, then there will be abundant hiding places (and microscopic food) for the offspring. How many you raise depends less on initial feeding (some do well on infusorians, others don't need it) than on the size of the grow-out tank.

What to do when you see fry in the tank? Remove the parents to another location, and let the young occupy the breeding tank as their grow-out tank. That's another reason to start with a bigger tank.

Ctenopomas should have a size-based diet, with frozen brine shrimp and bloodworms plus live blackworms or whiteworms for the smaller species, and feeder guppies and crushed snails for the bigger ones like C. kingsleyae.

Don't' use catfish in ctenopoma tanks, as they'll find and eat the eggs and fry before you see them. Instead, keep plenty of snails, cypris, or scuds in the tank as cleaners.

Here's a partial list of species to give you an idea of how much diversity you'll find in the group: Ctenopoma acutirostre, ansorgii, ashbysmithi, damasi, garuanum, intermedium, kingsleyae, lineatum, machadoi, maculatum, murieri, nebulosum, nigropannosum, ocellatum, pellegrini, and petherici; Microctenopoma congicum, damasi, fasciolatum, milleri, multispine, nanum, nigricans, ocellifer, pekkolai, and uelensis. By the time you read this, a few may become synonyms and other species may be discovered and named.

I'd be glad to hear of your successes with any of the ctenopomas, and so would our readers.

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