Geographical Distribution: Amazon and Araguaia-Tocantins basins. Successfully introduced in tanks of Prataand San Francisco basins and in weirs of the Northeast.

Description: Its family is mostly from saltwater, but it features several representatives in freshwater as well, being Plagioscionthe most common genus. They are fishes with scales; bluish silver coloration; oblique mouth with a large number of curved and pointed teeth. They have teeth in the pharynx and the anterior part of the branchial arches presents sharp projections with jagged inner edge. They can reach more than 1.60 ft long.

Ecology: Demersal and mid-water species, sedentary, forming large shoals in the central portion of lakes, ponds and tanks. They feed on fish and shrimp.