Type locality is given simply as ‘Amazon River, Brazil’ and according to current thinking this species has a huge natural range encompassing the Amazon River system in Brazil and Peru plus the Paraná-Paraguay drainage in southern Brazil and Paraguay and rio São Francisco basin in southern Brazil.

Specimens in our images were collected fro…

C. aurofrenatus is currently understood to occur throughout much of the Río Paraguay-Paraná system in Paraguay, and has also been recorded in Argentina and Bolivia.

It was described from Paraguay with type locality given as ‘Aguada near Arroyo Trementina’. The latter is stated to be a tributary of the ‘Rio Aquido Canigi’.

Apparently this species is polymorphic with body patterning varying significantly depending on locality. Individuals collected from black water habitats tend to be noticeably darker in overall colouration, for example, with this being particularly evident among populations from the Guiana Shield.

The genus Ageneiosus was at one point classified in…

An obligate piscivore capable of consuming surprisingly surprisingly large prey.

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-

Like the vast majority of predatory fishes this specie…

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 The grouping remains poorly-studied with the last major revision having been conducted by Watson (1990) in his unpublished dissertation, in which A. inermis was included under the currently synonymous name A. brevifilis.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 also known as the 'pearlscale' or 'mother-of-pearl' cichlid in deference to the iridescent body scaling. It's also worth noting that fishes sold as Gymnogeophagus australis in Europe are ‘G.‘ brasiliens is more often than not.

Wild specimens exhibits significant dissimilarities in body colour and patterning depending on locality with basic colouration being dominated by varying shades of blue, green or yellow, for example. Some populations al…

This species was formerly considered to be represented by the L-numbers L113 and L234 but it appears that only the former is native to the Paraná, Paraguay and Uruguay drainages, whereas L234 is collected in the rio São Francisco in eastern Brazil.

M. barrae and M. sp. ‘LDA097’ are also exported from the São Francisco system.

T. stellatus is superficially similar to its only congener T. securis, but can immediately be identified by the presence (vs. absence) of a prominent dark spot in the dorsal-fin. It is sometimes traded as ‘platinum hatchetfish’.

The genus Thoracocharax was originally erected by Fowler in 1906 as a subgenus of Gasteropelecus, but was elevated to generic status by Weitzman (1960).

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 assigned the ‘A’ number A204 under the DATZ system with possibly conspecific, related forms coded A205 or A206 depending on collection locality and representing populations from Argentina and the rio Guaporé, respectively.

The genus Apistogramma is among the most speciose of South American cichlid genera with around 70 species valid at present but many more awaiting description.