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.

This species, which may also be referred to by the alternative vernacular names 'spiny catfish', 'painted talking catfish' or 'chocolate raphael', isn't particularly common in the trade and most often exported only as bycatch among shipments of Platydoras armatulus. It appears very similar to A. cataphractus with the most useful external distinguishing character being the presence of pale blotches on the dorsal surface, between the dorsal and caudal fins, in….

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 The grouping remains poorly-studied with the last major revision having been conducted by Watson (1990) in his unpublished dissertation, in which A. inermis was included under the currently synonymous name A. brevifilis.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 spends almost all of its time at or just below the water surface, although it will sometimes retreat into midwater if threatened or feeding. Like other freshwater hatchetfishes, it is renowned for its ability to leap from the water surface and glide for distances of several metres. This behaviour is used both to catch flying insects, and to escape potential predators.

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…

R. vulpinus is the most widely-distributed member of the family Cynodontidae.

Type locality is given simply as ‘Brazilian rivers’, but this species is currently understood to be distributed in the Amazon basin from the Río Ucayali system in Peru, eastward as far as the rio Xingu in Brazil, plus the rio Tocantins and Rio Capim basins.

It’s also known from the Río Orinoco ba…

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.

Recorded throughout much of the Amazon basin, with its range extending eastwards from the Ucayali system in Peru as far as the Tocantins drainage which flows into the Atlantic alongside the Amazon at its delta. The southern extremity of its range appears to be the Río Mamoré in Bolivia, a tributary of the rio Guaporé, and the northern limit the Essequibo basin, Guyana.

Native to Guyana, where it may be restricted to the Potaro River, a major tributary within the Essequibo watershed.

It was described from aquarium specimens which were said to have been collected in ‘very small water courses of the Amazon’, but the type locality was corrected to ‘Guyana-Essequibo, Potaro River, Kuribong trail’ by Nijssen and Isbrücker (1980).