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…

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.

This species occasionally appears in the aquarium hobby, but the trade is largely reliant on commercially-produced ‘tiger barbs’ of questionable origin.

It was considered a synonym of P. anchisporus for a number of decades following Alfred (1963), but revalidated by Kottelat and Tan (2011).

The type series was collected from a small clear-water stream with a pH of 6.0, forming a series of riffles and deeper pools, with a maximum width of 5 metres and depth ranging from 10 cm to 1 metre. The substrate was composed of sand gravel and rocks, with some leaf litter and overhanging marginal vegetation.

Known only from affluents within the upper rio Tocantins basin draining into the enormous Serra da Mesa hydroelectric reservoir in Goiás state, Brazil. It has been collected from the rios Maranhão, das Almas, Traíras, and Palmerinha/Palmeira(?).

Type locality is ‘Brazil, Goiás, Rio Tocantins basin, Rio das Almas, tributary of left margin of Rio Maranhão, 14˚37′51.2″S, 49˚1′56.6″W’.

Retroculus spp. are unsuitable for the standard community aquarium, and should be maintained in a set-up designed to resemble a flowing river. The substrate should be composed of soft sand mixed with small pebbles if the aim is to breed the fish (see ‘Reproduction’). Rocks, boulders, roots, branches, and aquatic plants can also be added, although the la…

This fish is one of a number of apparently unidentified Scleromystax species known in the aquarium hobby.

The genus Scleromystax is included in the family Callichthyidae, of which members are often referred to collectively as ‘armoured’ or ‘mailed’ catfishes group due to the presence of bony plates in place of scales on the body.

It is most similar to S. macropterus, but differs in absence (vs. presence) of a black spot on the base of the median caudal-fin rays, a higher number of pectoral-fin rays (I,8,i vs. I,7,i), males with somewhat more slender bodies (25.7- 30.5% in SL [range 26.3-28.8% in type series] vs. 30.4-34.6% in SL), an…

Scleromystax spp. are foraging omnivores, and most will accept sinking dried foods as well as small live and frozen varieties such as chironomid larvae (bloodworm), Tubifex, etc. Feeding a varied diet will ensure the fish are in optimum condition.

Under no circumstances should they be expected to survive on ‘left-overs’ from other inhabitants of the aquarium or relied on to ‘clean’ the aquarium.

Known from minor rivers in the coastal states of São Paolo, Paraná, and Santa Catarina, southern Brazil, plus some tributaries of the rio Paraná basin in Paraguay.

Type locality is ‘Paranaguá, 25°32’S, 48°36’W, Paraná, Brazil’.