Known from the middle and upper Amazon river basins in Brazil, Peru, Ecuador and Colombia.

Type locality is ‘Amazon River at Obidos, Cudajas, and Tabatinga; Rio Negro, Brazil.’

It apparently practises an interesting reproductive strategy in which the eggs are deposited in a shallow depression excavated from the substrate and guarded by the male.

This species is relatively rare in the aquarium trade.

It can be differentiated from all congeners by a combination of possessing ctenoid (vs. cycloid) scales on the sides of the head plus lacking a dark spot at the caudal-fin base.

This species is available on a relatively regular basis, although it’s sometimes confused with the similar-looking congeners H. loretoensis and H. metae.

It can be identified via the following combination of characters as per Géry (1977): elongate in shape with body depth fitting 3.8-3.9 times in its standard length; caudal peduncle narrow, its depth fitting 1.8 times in its length; head short, interorbital broad, snout short and rounded; dorsal-fin insertion an…

The form from the Río Tigre, previously referred to as the subspecies C. p. orcesi (Weitzman & Nijssen, 1970) was raised to full species status as C. orcesi by Isbrücker (2001), but this decision does not appear to have been followed by all authorities some of which consider C. p. orcesi a synonym of C. pastazensis.

The two species are relatively easy to tell apart by colour pattern; in C. pastazensis the dark vertical…

This species is sometimes confused any of several similar-looking fishes such as C. sychri or C. sp. C097.

While the former is a more elongate fish with a longer snout and quite easy to identify, C097 resembles C. atropersonatus more closely, despite being traded as C. sychri ‘longnose’. Its snout is longer than that of C. atropersonatus but shorter than that of C. sychri, and the dark spots on the body tend to be more well-defined and spaced out than in the other two.

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.

A. bimaculatus is not a popular aquarium fish but is available on occasion exception, most often as a contaminant among shipments of other species.

It’s identity is also in question to an extent with the name currently applied to what is considered to represent a species complex comprising at least four taxa.