This species is a member of the putative A. nasutus group of closely-related species within the genus alongside A. nasutus, A. maculipinna and A. isalineae.

These are characterised by possession of two dark, longitudinal stripes, one running from the tip of the snout to the base and the other from the posterior edge of the lower maxilla to the underside of the caudal peduncle.

An obligate piscivore capable of consuming quite large prey in relation to its body size although it tends to focus on smaller prey such as tetras and related species.

Newly-imported specimens may refuse to accept anything but live fishes although most can be weaned onto dead alternatives once they recognise them as edible, and some even learn to accept dried foods.

The genus Ageneiosus was at one point classified in the family Ageneiosidae alongside the genus Tetranematichthys, but this was not accepted by all authors. The grouping remains poorly-studied with the last major revision having been conducted by Watson (1990) in his unpublished dissertation, in which A. inermis was included under the currently synonymous name A. brevifilis. It can be separated from the majority of the genus (except A. marmoratus) by possession of a truncate caudal fin, and from…

This species is generally rare in the aquarium hobby though oddly appears to be one of the commoner species in Australia where it’s often referred to by the vernacular name ‘black-throated eartheater’. It’s a member of the nominal G. surinamensis ‘group’ of closely-related species within the genus and can be identified by a combination of characters including: presence of dark preopercular markings; no vertical bars on the flanks even when stressed/preserved; base of filaments on the first gill arch mostly covered by a flap of skin; exposed part of bra…

This species is very rarely-traded since collections of fishes for commercial purposes aren’t common in Suriname. It’s a member of the nominal G. surinamensis ‘group’ of closely-related species within the genus and can be identified by a combination of characters including: no dark preopercular marking; six vertical/parallel bars on each flank (normally visible only when the fish are stressed, spawning or preserved); dark, squarish lateral spot positioned within the third vertical bar; sixth (posterior) bar elongate an…

C. strigata is an enduringly popular species in the aquarium hobby but is not bred on a commercial basis with all fish offered for sale collected in the wild.

It can be told apart from other members of the genus by its larger adult size and dark, marbled colour pattern appearing as a series of dark and light stripes running diagonally across the body below the lateral line.

This colour pattern is variable and popul…

This species is currently the only described member of its genus although colour pattern and morphology vary considerably across its range.

You may see reference to this species being the only fish species to possess infra-red vision, but other species also possess this ability and we suspect that infra-red plays an important role in the reproductive cycle of many fishes.

C. brevirostris was described from an aquarium specimen apparently exported from the Río Orinoco drainage in Venezuela, and its wider distribution is somewhat vague, usually being given as the Orinoco system plus unnamed coastal rivers in Suriname.

This represents a somewhat disjunct pattern of distribution and if correct the species is also likely to occur in Guyana.

Type locality is ‘Río Yuruari, 3 kilometers east of El Callao, 7°18’N, 61°50’W, Bolivar, Venezuela’, and this species is also known from the Rupununi River drianage in Guyana and the Courantyne/Corantijn system in Suriname.

The Yuruari, an affluent of the Río Cuyuni, an…

This species may also be seen on sale as 'Guyana slopehead catfish' 'dolphin catfish' or 'hammerhead catfish'. The attractive juvenile patterning is largely lost as the fish grow but this nevertheless remains an impressive predatory species for the larger aquarium.

The genus Ageneiosus was at one point classified in the family Ageneiosidae alongside the genus Tetranematichthys, but this was not accepted by all…