Vernal pools are the ephemera of wetlands. They come to life with the rain or rising streams of spring, dry up by fall, then return the following spring. Due to their cyclical nature, the pools cannot support fish. As a result, entire ecosystems have evolved in the safe haven vernal pools offer away from their biggest natural predators: fish. Animals that thrive in vernal pools include salamanders, wood frogs, and fairy shrimp, to name a few.