It may not rain cats and dogs, but sometimes it rains tadpoles and tiny fish. This strange meteorological event is probably caused by waterspouts, basically tornadoes that form over water.
Waterspouts start out as vortexes, or columns of rotating, cloud-filled wind. As the vortex descends over an ocean or lake, small aquatic animals may be swept up in the waterspouts funnel.
Changes in pressure and wind force the waterspout to change back into a low-lying cloud, emptying precipitationincluding any creatures swept up in the waterspoutover a nearby landmass.
In 1894, newspapers in Bath, England, reported a rain of tadpoles. In 2009, a storm brought a rain of minnows down on Ishikawa, Japan.