The Red Bellied Piranha (Pygocentrus nattereri) is a species of Piranha from the family Characidae and the genus Pygocentrus. It is a small freshwater fish living naturally in the Amazon River. It feeds mostly on other animals, like fish and insects. A full grown specimen is usually around 12 inches long. Young ones have a silvery body, but when they are in adulthood, they are identified with a red "belly", thus the name. Its teeth are triangular and extremely sharp. A single specimen would only cause little, non fatal damage on a person, but this species hunts in large packs.
This fish is identified as the most ferocious fish in the world, causing several deaths.