Das Mortes

This species was available in the hobby several years prior to being described, invariably traded as G. sp. aff. altifrons 'Tocantins', G. sp. 'Tocantins' or G. sp. 'rio Areoes'. The latter of these names refers to an Indian reserve named 'Areões' in the rio Das Mortes drainage, a tributary of the Araguaia which itself drains into the Tocantins, and the aquarium specimens in our images have been identified as G. neambi by Dr. Paulo Lucinda, co-describer of the species.

Type locality is 'Rio das Mortes, some 100 km before its confluence with the Braço Maior of the Rio Araguaia (the western border of the Isla do Bananal). State of Mato Grosso.' The das Mortes is a principal tributary of the Araguaia, itself the major affluent of the rio Tocantins within the lower Amazon basin in central and western Brazil, although the full range of H. amandae within the Araguaia system is unclear.

In the aquarium hobby the name Hyphessobrycon stegemanni has frequently been misapplied to a species that has been described as Hemigrammus ataktos Marinho, Dagosta, & Birindelli 2014. The reasons for this confusion are presumably that the two occur sympatrically in the rio Tocantins system and both possess a dark lateral stripe on the body.

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...