Tornadoes can cause "fish rain."

Tornadoes can develop over water just as well as they can over land. When they do, they're called "waterspouts," and they suck up large amounts of lake or sea water—as well as whatever's swimming in that water. If the waterspout travels on to the land and the winds decrease, there's nowhere for those fish to go but down. As far as we know, there's no tornado powerful enough to pick up sharks, but a fish-nado is entirely possible.