Endemic to the Paraguay, Paraná and Uruguay river drainages in Brazil, Paraguay, Argentina and Uruguay.

The smallest of the three Aphyocharax species seen in the hobby, the redflank is relatively uncommon in the hobby in the aquarium trade.

It is also known as the Green Fire Tetra.

A good beginner’s tetra, as it’s a hardy species that will adapt to a relatively wide range of conditions. In a well-insulated house it can even be kept in an unheated tank, although it won’t be as colourful as when kept in warmer water.

It’s also quite long-lived and captive specimens over ten years old are not unheard of…

Generally peaceful making it an ideal resident of the well-researched community aquarium.

It is perhaps best-maintained alongside similarly-sized characids, gasteropelecids, lebiasinids, smaller callichthyid or loricariid catfishes and non-predatory, medium-sized cichlids.

Try to buy a mixed-sex group of at least 8-10 specimens, incl…

Widely-distributed throughout much of the Paraná and Uruguay river systems in Brazil, Paraguay, Argentina and Uruguay.

Some records from Buenos Aires province, Argentina are now considered to refer to the congener H. togoi (Miquelarena and López, 2006) so the common vernacular name ‘Buenos Aires tetra’ may not…

Its native rivers flow through one of the most densely-populated and industrialised parts of Brazil, and have suffered greatly from dam construction, water abstraction, pollution, introduced species (including over 40 exotic freshwater fishes in the rio Paraíba do Sul alone), and other forms of anthropogenic degradation. H. flammeus is now uncommon or even extinct across much of its putative natural range, and in Rio de Janeiro state only a handful of highly-fragmented populations remain at best, with the mo…

This species is very common in the aquarium trade and is also referred to as ‘jewel’, ‘red minor’, ‘blood’, or ‘callistus’ tetra.

A number of selectively-bred ornamental strains have been developed, including ‘metallic’, ‘long-finned’, ‘balloon’ and ‘fairy-fin’.

Characiformes is among the most diverse orders of freshwa…

It exhibits slightly different behaviour to the majority of congeners in that it tends to swim in midwater and spends a large proportion of its time away from the substrate. Its morphology exhibits corresponding adaptations towards a pelagic existence with a relatively large eye, a more terminal mouth position, more strongly-forked caudal-fin, and more symmetrical body shape than most other Corydoras species.

Despite the ubiquity of its name in aquarium literature, confusion surrounds its true identity. Given it’s the only member of the genus occurring on the island, fish from Trinidad do presumably represent C. aeneus (see our image), but the classification of those from other localities appears far from certain.

Today the species is accepted to occur throughout much of South America, and indeed similarly-patterned fish do occur across a large portion of the continent. Some of these, such as the gree…

Abramites spp. are separated from other anostomids primarily on the basis of their relatively deeper bodies and presence of a prominent, post-pelvic median keel, a feature unique to the genus.

At time of writing A. eques is the only other species recognised and is native to the Río Magdalena drainage in western Colombia.

It can be distinguished by possession of 13-14 bra…

Wild fish are probably foragers feeding on algae, organic detritus, small insects, worms, crustaceans, and other zooplankton.

In the aquarium it’s easily-fed but the best condition and colours offer regular meals of small live and frozen foods such as bloodworm, Daphnia, and Artemia, alongside good quality dried flakes and granules, at least some of which should include additional plant or algal content.