German botanist Joseph Gottlieb Kölreuter was responsible for the 1763 description, while Swedish taxonomist Carl Linnaeus prescribed its first true scientific name - Salmo argentinus - in 1766.

[3] It has a generally slender body with a deep chest and long pectoral fins, which are characteristics that differentiate Piabucus from sister genus Iguanodectes.

[6] Congener Piabucus melanostoma has a distinctive patch of dark coloration on the lower jaw often absent in related species, but similar markings can be found on some specimens of P.

[10] Males from all three species of Piabucus also develop lappets (fleshy extensions) and small hooks on the foremost few rays of the anal fin.

[17][18] Marcgrave's Piabucu is considered in modern research to be equivalent to P. dentatus, making it one of the earliest-recorded South American fishes in Northern ichthyology.

[25] (To this day, dentition - or lack thereof - remains a morphometric feature that can be used to differentiate fish species of similar superficial appearance.

It demonstrates a preference for silty, turbid waters, including estuaries, floodplain streams, and various river tributaries, which places it in some brackish environments.

[31] Examination of stomach contents has shown that P. dentatus is a generalist feeder with a preference for algae and decaying plant matter, though it also targets microscopic invertebrates.

Hobbyists report a generally pleasant disposition, but its large size in comparison to other aquarium tetras results in an intimidating presence for smaller fishes;[35] still, it is often an appropriate addition to a community tank.

[1] While it lives in habitats under various anthropogenic pressures, including dam construction, oil drilling, and infrastructural development, there is no evidence of an immediate population threat.

For instance, one study demonstrated that hydroelectric dam construction decreased general species diversity, but P. dentatus in particular seemed to suffer only mild consequences.