Poecilia mexicana

Poecilia mexicana, commonly known as the Atlantic molly, is a species of poeciliid fish native to the Atlantic slope of Middle America. The species is highly variable in coloration, shape, and size. Atlantic mollies occur in fresh and brackish waters, shallow and slow-flowing or standing. They feed chiefly on algae and detritus. Two populations are found in caves and represent some of the best-studied cavefish. It hybridizes with other Poecilia species in its range; one such cross has resulted in the unisexual P. formosa.