Das Mortes

Geophagus neambi is a cichlid from the mid-to-upper rio Tocantins in Brazil, to which it may be endemic. It was in the hobby several years before it was described, traded as G. sp. aff. altifrons 'Tocantins', G. sp. 'Tocantins' or G. sp. 'rio Areoes', and aquarium fish are apparently collected in the rio Das Mortes basin. The 8-9 flank bars are normally visible only when the fish are stressed or spawning.

The ember tetra, Hyphessobrycon amandae, is a tiny characid from the rio das Mortes, a tributary of the Araguaia in Mato Grosso, Brazil. Also traded as the 'Amanda's', 'dwarf red', 'red' and 'fire' tetra, it grows to around 20 mm SL. Very peaceful and gregarious, it makes a good dither fish for Apistogramma and other dwarf cichlids and spawns often in a mature aquarium.

The savanna tetra, Hyphessobrycon stegemanni, is a characid from the middle rio Tocantins and rio Araguaia basins in central Brazil. In the hobby its name has often been misapplied to Hemigrammus ataktos, since both occur in the Tocantins and have a dark lateral stripe. Its range lies almost entirely in the cerrado, the tropical wooded grassland of central Brazil.

Retroculus lapidifer is a rheophilic cichlid from the rio Tocantins and Araguaia systems and nearby coastal drainages of northeastern Brazil. It lives in rapids and fast-flowing stretches of clear water rivers, and needs a set-up designed to resemble a flowing river, with a base of at least 210 by 60 cm and water of 26 to 32 °C. A biparental substrate-spawner, it has been bred in aquaria and is available in the trade on a sporadic basis.