Piranha II: The Spawning (1982)

A sunken US supply ship off a Caribbean island resort is the focus for a series of mysterious piranha attacks. Investigating the death of one of her son's companions after a scuba-diving trip, Anne Kimbrough breaks into the morgue with holidaymaker Tyler Sherman, only to discover that the fish have wings and can fly. But the hotel manager refuses to call off the annual fish fry on the beach, with inevitable consequences...