Megapiranha magnadmorsus is carnivorous fish found fairly commonly in the rivers and ponds of the island. Its bite is incredibly powerful; I've even seen them break through the armored turtles of the island. Megapiranha has one of the strongest bites, pound-for-pound, of any creature on the island.
Like some of the other creatures on the island, a tamed Megapiranha is best suited as a guard. Their high metabolism makes them require more food than many other creatures, but they are very adept at hunting their own food, particularly the Coelacanths.
When encountering a Megapiranha, be on the lookout for the rest of the school. No one Megapiranha is an overwhelming threat, but their tendency to swarm prey can make short work of much larger and stronger creatures. Any given Megapiranha is easy to kill, but killing the entire school can be a daunting task.