São João

The flame tetra, Hyphessobrycon flammeus, is a small characid from Rio de Janeiro and São Paulo states in Brazil. Popular in the hobby, it is bred commercially in several countries and also sold as 'red', 'fire', 'rio' and 'Von Rio' tetra. In nature it is now uncommon or even extinct across much of its range, and the São Paulo populations may have been introduced by aquarists or breeders.

The sailfin 'cory', Scleromystax macropterus, is an armoured catfish from coastal rivers of southern Brazil and the rio Paraná basin in Paraguay. Most have been collected from small blackwater streams draining directly into the Atlantic, but it also inhabits roadside ditches. Males are somewhat territorial towards one another and should not be kept together in smaller aquaria, and its stiffened pectoral-fin spines can give a painful 'sting'.

Scleromystax prionotos is an armoured catfish known only from coastal rivers in Minas Gerais, Espírito Santo, Rio de Janeiro and São Paulo, Brazil. Like its congeners it is a facultative air breather and occasionally rises to gulp air at the surface. Its stiffened pectoral-fin spines can pierce human skin, so care is needed when handling it.