This species is sometimes confused with B. juruense, especially when juvenile, but can be told apart quite easily by it’s more well-defined colour pattern, relatively slender body shape and longer barbels. It was described in the genus Meredontotus, but is currently included in Brachyplatystoma based on a pair of synapomorphies shared by memb…

The genus Acarichthys remains monotypic and was resdescribed by Kullander (1986) who characterised it by the following: lack of epibranchial lobe; comparatively few (12-14)rays; pelvic fins with relatively broad tips (branches of the first ray are equal in length or the inner is slightly longer); possession of a single supraneural plus 14-15 vertebrae (these characters taken as a combination); no caudal extensions to swim bladder; no caudal ribs.

Its current taxonomic position is based largel…

One of the most popular and instantly recognisable fishes in the aquarium hobby, this species has been selectively-bred to produce a number of additional strains including albino, ‘golden’ (leucistic), short-bodied, long-finned and ‘diamond’ (in which the dorsal surface is covered in reflective scales).

Unfortunately years of commercial breeding have somewhat affected the genetic vigour of the ornamental strain meaning morphological defects an…