THIS STRIPED SWIMMER IS A PICKY EATER, DINING ON ONLY TABULAR AND staghorn corals. Normally, that’s fine. Both fish and corals live in waters all over the world, from Hawaii to the Red Sea. But ocean temperatures are rising, killing the corals in massive bleaching events in which they lose their symbiotic algae. When cyclones smash up the already vulnerable reefs, fish suffer all the more. It’s possible some outposts of butterflyfish will survive, waiting to return to their old haunts should corals ever recover. But that process could require that seas stay calm and cool for a decade or more.