Robert J. Goldstein, Ph.D.
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
and found that the genus Ctenopoma consisted of two distinctive
evolutionary lines. 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 similarity 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
or gal, 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 that they had grown too big for their
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
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 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 are left over and rot). 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,
there will be abundant hiding places (and microscopic food) for the offspring
should the fish breed. 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
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
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.