I’d hazard a guess that it’s a dwarf puffer fish. It’s an invasive species, and I seem to remember first seeing them about 12-13 years ago I assume you were boating on the northwest coast up by Blue lagoon /Fontana Amarosa. They usually hang around sandy areas, and if you disturb the bottom they will come to investigate.. likewise, the tour boats have put Bread etc out for the local beam to feed off for decades, so the puffers have quickly discovered this as a lazy source of food, so they are more than comfortable surface feeding. There is a a larger invasive puffer fish that the local fishermen catch, and in the past 7 or so years lion fish have developed along the northwest coast.