Members of this assemblage can be told apart from other congeners by possession of 44–46 vertebrae, an adipose-fin with a relatively short base (< 20 % SL), a colour pattern comprising either distinct black spots arranged in vertical columns or irregular black vertical lines running along the flanks, and normally a reddish or orangish caudal-fin in life.

This species appears to be unknown in the aquarium trade but is a valued food fish within its native range.

Hemibagrus has been divided into a number of putative species groups which may or may not represent monophyletic assemblages, and following a major review by Ng and Kottelat (2013) H. filamentus is included in the H. nemurus group.

This species is not available on a commercial basis but was collected and introduced to the aquarium hobby by Hans Georg-Evers in 2010.

It’s similar in appearance to a number of congeners including C. diphyes, C. erhardti, C. garbei, C. paleatus and C. steindachneri but can be told apart from most of them by possession of two large, indistinct, dark blotches in the middle of each flank.

This species appears endemic to and abundant within the upper Suriname River system, Suriname.

Type locality is given as ‘little tributaries of Gran Rio between Ligolio and Awaradam Falls’, this corresponding to a section of the Suriname River, which is known as ‘Gran Río’ in parts of its upper basin, upstream of Brokopondo reservoir and not…

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’.

C. amandajanea is rare in the aquarium trade and appears to be variable in colour pattern to an extent, with some individuals posssessing relatively larger dark spots on the body, for example.

Unfortunately diagnostic characters cannot be provided since we’ve been unable to obtain the type description, and little has been written about this species since it was published.

In the upper Iténez it most commonly inhabits riparian zones with sandy substrates or edges of sand banks, although it’s also been collected in smaller streams and residual flood waters.

It typically forms large aggregations of up to several thousand individuals and at the confluence of the ríos Paraguá and Iténez occurs sympatrically with the congener C. paragua.

This species can be confused with three similar-looking fishes of uncertain taxonomic status which have been assigned the C numbers C024, C077, and C109 in the aquarium hobby.

C024 and C109 are unlikely to be conspecific in that they occur in Pará state, Brazil, several thousand kilometers outside the range of C. acutus, in the rio Guamá (Tocantins drainage), and lower rio Xingu, respectively.

Type locality is ‘Furo do Lago São Francisco, 7°40’S, 72°39’W, tributary at left bank of Rio Juruá, Acre State, Brazil’, and C. acrensis appears to be endemic to the rio Juruá basin.

Unfortunately diagnostic characters cannot be provided since we’ve been unable to obtain the type description, and little has been written about this species since it was published.

Several Brachyrhamdia species have developed colour patterns that mimic syntopically-occurring Corydoras spp. throughout the life-cycle, and the remainder, including B. meesi, may mimic Otocinclus or smaller Corydoras spp. when juvenile. They’re easily told apart from Corydoras by their significantly longer barbels and lack of scute-like plates on the body.