Red piranha (Pygocentrus nattereri) The red piranha of South America is notorious for its ferocity which, allowing for popular exaggeration, is still formidable. It has powerful jaws full of very sharp teeth, and makes up for its small size – 35 cm (14 in) long at the most – by swimming quite often in large shoals. These represent a threat to larger fish and land animals and even to man. They feed in bouts rather than continuously and locate their prey by means of their sense of smell which leads them, for example, to any flesh that has already been torn and is bleeding. They will eat dead flesh as well.