Poeciliidae

aquarium fish · live-bearing · freshwater

Amazing aquarium stars. Guppies, mollies, platys, and swordtails all belong to this family, and they're some of the most popular pet fish in the world because they're beautiful and easy to care for.

Babies born alive. Unlike most fish that lay eggs, poeciliids give birth to live baby fish, which is pretty unusual and makes them fascinating to watch in tanks.

From Americas to everywhere. These fish originally lived only on the Atlantic side of the Americas, from the southeastern United States all the way down to Argentina, but people brought them to tropical areas worldwide.

Mosquito hunters. People released Gambusia and Poecilia fish into wild areas on purpose to eat mosquito babies, which helped stop diseases but also spread these fish to new places they'd never naturally reach.

Hardy heat lovers. These fish are so tough that scientists have found them living in hot spring pools way up north in Banff, Alberta, where most tropical fish couldn't possibly survive.