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. hujeta is traded under various names including 'slant-nosed gar', 'hujeta gar', 'rocket gar' and 'freshwater barracuda' but it and other members of the family Ctenoluciidae have traditionally been referred to as 'pike characids'. They're all predatory fishes native to South America, included in the order Characiformes and currently spread across two genera; Ctenolucius with two species and Boulengerella with five.

The two genera are …

Quite widely distributed having been recorded from Brazil, Colombia, Peru and Venezuela. It’s been collected from the upper parts of several major river drainages including the Río Negro, Río Orinoco (including the Río Inírida and Casiquiare canal) and Río Solimões.

The type series was collected from ‘Igarapé Préto’, Brazil, said to be 60 kilometres to the south of the Colombian border city Leticia. Populations from Colombia and Brazil tend to be more intensely-coloured, and the Peruvian populations may apparently represent an undescribed species.

The majority of records derive from the Río Apure watershed in southwestern Venezuela, where C. habrosus has been collected in the states of Portuguesa, Cojedes, Barinas, Guárico, and Apure. Its distribution in Colombia is less clear but it is known with certainty from the Río Arauca and Río Casanare, the latter a tributary of the lower Río Meta, and it makes sense that it should also be found in other left bank Orinoco affluents between the Meta and Apure, which include the ríos Cinaruco and Capanaparo.

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…

The vernacular name of this fish is derived from its appearance and behaviour, rather than a genetic association with the marine barracuda, and it’s also sometimes referred to as ‘pike characin’ or ‘spotted cachorro’ with local vernacular names including ‘Grand dent-chien’ (French Guiana), ‘ Cachorrinho’ or ‘Ueua’ (Brazil).

Although most species of Acestrorhynchus appear superficially similar to one another most exhibit distinguishable external chara…

This species is also referred to as ‘South American puffer’, ‘SAP’, ‘Amazonian puffer’, ‘Peruvian puffer’, or ‘Brazilian puffer’ in the ornamental trade.

Within the genus Colomesus, C. asellus can be immediately identified by possessing a unique transverse row of dermal flaps across the chin which is absent in its congeners C. psittacus and C. tocantinensis.

This is the type species of the genus, fairly ubiquitous in the aquarium trade, and represents an excellent choice for the newcomer to fishkeeping since it’s less demanding than most congeners. It’s sometimes referred to as ‘Beckford’s pencil fish’ or ‘brown pencilfish’.

Don’t worry if your fish look different when you switch on the aquarium lights after dark or in the morning as like most Nannostomus species it assumes a cryptic, vertically-barred colour pattern at ni…