Pirahnas are omnivores and feed on plants, seeds, fish, worms, and insects. They will also eat birds or mammals that fall into the water (alive or dead). Although they have a reputation for devouring large animals such as cows, this is uncommon and occurs only in times of extreme food shortage or stress.
South American rivers including the Amazon River. They are found in shallow lagoons, creeks and rivers in groups called shoals.
Pirahna are schooling fish that use their numbers to protect against predators such as large fish, river dolphins and birds.