Tahuamanu

The smallest and most delicate of the nominal hatchetfishes. The rounded keel is shallower than related species, giving this fish a distinctive elongate profile. The family Gasteropelecidae is separated from other Characiformes by the following combination of characters: front...

This species is relatively common in the aquarium hobby but is not easy to maintain and recommended only for experienced aquarists. It can be told apart from all congeners by specimens larger than 60 mm SL possessing an extended pectoral-fin spine forming an extremely long filament that may be more than four times the length of the first branched pectoral-fin ray (vs. not possessing such a filament in other species of Lamontichthys).

This species appears endemic to the upper rio Madeira basin in Bolivia and Brazil. Records exist from the Río Mamoré and Río Guaporé drainages in Bolivia (where the Guaporé is known as the Iténez) and Brazil plus the upper Río Orthon (ríos Tahuamanu and Manuripi). Type locality is 'sand-bank in the Rio Marm...

Famed as a rapacious predator capable of rapidly stripping flesh from bone and a danger to any animal entering its native waters, P. nattereri is among the most notorious freshwater fishes in the world. As a result, displays featuring this “bloodthirsty” creature are found in most public aquaria, grisly Hollywood movies have been released, and the species has become popular in the aquarium trade. Little of this infamy is based on factual evidence, however.

T. stellatus is superficially similar to its only congener T. securis, but can immediately be identified by the presence (vs. absence) of a prominent dark spot in the dorsal-fin. It is sometimes traded as 'platinum hatchetfish'. The genus Thoracocharax was originally erected by Fowler in 1906 as a subgenus of Gasteropelecus, but was elevated to generic status by Weitzman (1960).