Hydrolycus armatus

Hydrolycus armatus is a species of dogtooth characin found in freshwater of tropical South America. It is sometimes known as the black-tailed payara, payara, silver payara, or harm, a name it shares with the related H. scomberoides and H. tatauaia.

This predatory fish occasionally makes its way into the aquarium trade, but it requires a very large tank. In its native range it is considered a major gamefish.