It was just bones. Once a piranha reaches about one inch, it starts eating other fish, but until then they eat only plants and plankton. They could smell blood over 500 feet away. BODY Piranhas have razor sharp, triangle shaped, pointed teeth. These teeth are so strong they could easily cut through a bone.
Piranhas are partly bluish green on the top and the sides with red bellies.
They can grow to be two feet long, but mostly no more than eight inches. They do not weigh more than four pounds. Other than sharp teeth, they have a protruding jaw. The lower jaw is just a little longer giving them a slight under bite. This helps them to tear flesh more efficiently.