Colomesus

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.

Although it does penetrate the lower basins of rivers, particularly the Amazon where it has been collected from the rio Xingu several hundred kilometres from its mouth, this species is predominantly an inhabitant of mangrove swamps, estuaries, and other such saline habitats. It is particularly common in tidal channels, shallow inshore lagoons, and the lower reaches of rivers.

It is distinguished from congeners by the following combination of characters: anal-fin with 6-7 basal pterygiophores and 9 rays (vs. 10-11 rays in C. asellus and C. psittacus; dorsal-fin with 10 bas...