[2] The wimple piranha is found in the Amazon, Orinoco, Essequibo, and upper Paraguay River basins in South America.

[3] This species inhabits clear freshwater streams and lakes with abundant submerged vegetation.

[3] The curve of its large, banana-shaped lower jaw creates a distinctive protuberance; this gave this fish the specific name mento, which means 'chin'.

[3] The dietary breadth of the wimple piranha is one of the narrowest reported for fishes; scales form an important proportion of the diet throughout most of its life, and adults feed almost entirely on them (see lepidophagy).

However, to feed on scales attached to fish, it uses ram feeding, where the predator will charge at the fish; the force of this collision actually knocks scales free.