Ctenopoma acutirostre PELLEGRIN, 1899

Leopard Bushfish

Etymology

Ctenopoma: from the Ancient Greek κτείς (kteís), meaning ‘comb’, and πῶμα (pôma), meaning ‘lid, cover’, used here in reference to the operculum.

acutirostre: from the Latin acutus, meaning ‘sharp’, and rostrum, meaning ‘snout’.

Classification

Order: Perciformes Family: Anabantidae

Distribution

Widely distributed throughout the middle Congo River basin in Republic of the Congo, Democratic Republic of the Congo, and Central African Republic, from Malebo (Stanley) Pool upstream to Boyoma (Stanley) Falls. It occurs in several major tributary systems, including the Kasai, Lefini, Ubangi, Tshuapa, and Lomami.

Type locality is ‘Diélé, Congo’.

Habitat

In the Salonga National Park, Democratic Republic of the Congo, sympatric fish species include Polypterus spp., Pantodon buchholzi, Xenomystus nigri, Gnathonemus petersii, Phractolaemus ansorgii, Hepsetus odoe, Alestopetersius spp., Phenacogrammus interruptus, Distichodus decemmaculatus, D. noboli, Nannocharax spp., Neolebias trilineatus, Pareutropius debauwi, Schilbe spp., Clarias spp., Synodontis contracta, S. decora, S. flavitaeniatus, S. nigriventris, S. schoutedini, Epiplatys chevalieri, Congopanchax brichardi, Parachanna obscura, Ctenopoma kingsleyae, C. nigropannosum, C. weeksii, Microctenopoma ansorgii, M. fasciolatum, M. nanum, Congochromis dimidiatus, Hemichromis spp., Pelmatochromis nigrofasciatus, Tilapia spp., and Tylochromis aristoma.

Maximum Standard Length

100 – 150 mm.

Aquarium SizeTop ↑

An aquarium with base dimensions of at least 120 ∗ 30 cm or equivalent is recommended.

Maintenance

Prefers a dimly-lit aquarium with a layer of surface vegetation, such as Ceratopteris spp., plus some submerged cover. Driftwood roots and branches plus plant species such as Anubias can be used to achieve the latter, while the addition of dried leaf litter is also recommended.

Water Conditions

Temperature: 20 – 28 °C

pH: 5.5 – 7.5

Hardness: 36 – 215 ppm

Diet

An obligate predator which probably feeds on smaller fishes and invertebrates in nature, but in most cases adapts well to dead alternatives in captivity. Some specimens may accept dried foods though these should never form the staple diet.

Young fish can be offered chironomid larvae (bloodworm), small earthworms, chopped prawn and suchlike, while adults will accept strips of fish flesh, whole prawns, mussels, live river shrimp, larger earthworms, etc.

This species should not be fed mammalian or avian meat such as beef heart or chicken since some of the lipids contained in these cannot be properly metabolised by the fish and may cause excess fat deposits and even organ degeneration. Similarly there is no benefit in the use of ‘feeder’ fish such as livebearers or small goldfish which carry with them the risk of parasite or disease introduction, and tend not have a high nutritional value unless properly conditioned beforehand.

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Sexual Dimorphism

Males have more spines on the gill covers, and a roughly-textured area at the base of the caudal peduncle that is absent in females.

Reproduction

There are very few reports of this fish spawning in aquaria. The chances of obtaining a suitable pair should be higher if you buy a group of young fish, allowing these to pair off naturally.

The spawning tank should be large and contain lots of floating plants. The tank should have the tightest-fitting cover you can find, as the fry need access to a layer of warm, humid air. Without this, the development of the labyrinth organ can be impaired. Apparently the pair embrace in the usual anabantoid fashion at which point eggs and sperm are released. The eggs float to the surface where they come to rest in the floating vegetation. The adults exhibit no parental care and should be removed at this point.

The eggs hatch after 48 hours and the fry become free swimming quite quickly. Infusoria should be offered for the first 2 days after which they will accept brine shrimp nauplii. Despite the fish having been bred several times in aquaria, it appears that fry survival rate is usually quite low. This may well be related to cannibalism as much as anything else. Brood size, on the other hand, can be enormous. Several thousand eggs may be deposited, so if you intend to have a go at spawning these, be sure to have plenty of space ready for the young fish.

It is thought that C. acutirostre and other egg-scattering Ctenopoma may be seasonal spawners as a pair will often spawn regularly for several months and then stop for a while. This does not appear to be related to water temperature or other parameters. There is also a general school of thought that the species does not become sexually mature until it is 5-10 years old.

NotesTop ↑

An ideal species for the newcomer to ‘oddballs’. It is exceptionally hardy, long-lived (it can survive for over 15 years when cared for properly) and exhibits some interesting behaviour. It appears to have evolved convergently with leaf fish of the genera Polycentrus and Monocirrhus (they’re not closely related). All these species mimic leaves and other aquatic debris to assist them in hunting their prey. If you add live food to its tank, you will see the typical stalking behaviour, which is great fun to watch.

It goes by several common names, and is often sold as ‘spotted climbing perch’. While it is indeed related to Anabas species, it is not known to have the ability to cross areas of dry ground.

Like others in the suborder Anabantoidei, the species possesses an accessory breathing organ known as the labyrinth organ. So-called due to its maze-like structure, this organ allows the fish to breathe atmospheric air to a certain extent. It is formed by a modification of the first gill arch, and consists of many highly vascularised, folded flaps of skin. The structure of the organ varies in complexity between species, tending to be more well-developed in those inhabiting particularly oxygen-deprived conditions.

References

1. Pellegrin, J., 1899 - Bulletin du Muséum National d'Histoire Naturelle (Série 1) 5(7): 357-362
   Revision des exemplaires du genre Ctenopoma de la collection du Muséum et description de trois espèces nouvelles.
6. Monsembula Iyaba, R. J. C. and M. L. J. Stiassny, 2013 - Check List 9(2): 246-256
   Fishes of the Salonga National Park (Congo basin, central Africa): A list of species collected in the Luilaka, Salonga, and Yenge Rivers (Equateur Province, Democratic Republic of Congo).