The piranha is known as being one of the deadliest fish in South America, due to its sharp teeth and strong jaw bone. Piranhas are found in South American lakes, rivers, and water reservoirs. Although they are known to be very deadly, they are actually omnivores, meaning they eat plants and animals. Their typical diet consists of fish, birds, reptiles, fruits, seeds, and leaves. They may also eat larger mammals but typically only if they are injured.