Photos from Pygocentrus nattereri South American Characidae:
These photos are pretty dated, and some are in very poor quality.
Pygocentrus nattereri photo gallery:
The Red-bellied piranha (Pygocentrus nattereri) is a species of piranha. This species lives in the Amazon River Basin, coastal rivers of north-eastern Brazil, and the basin of the Paraguay, Paraná and Essequibo Rivers. The red-bellied piranha has the reputation for being one of the most ferocious freshwater fish in the world. They have a set of razor sharp teeth which are capable of stripping flesh from prey and dead animals. As their name suggests, they have a reddish tinge to the belly when fully grown, although juveniles are a silver colour with darker spots. They grow to a maximum length of 13 inches (33 cm) and a weight of 7.7 pounds (3.5 kg) .(read more)