The Molly (Poecilia latipinna) is a popular freshwater aquarium fish species. It is a member of the Poecilidae family and is therefore live-bearing. It prefers hard water and can withstand a surprising degree of salinity. Indeed, mollies can be habituated to full-strength sea-water and live in a marine aquarium if need be. Mollies are more herbivorous than most aquarium fish and have a tendency to consume aquarium plants.

The species originates in the coastal areas of central America, on the Caribbean costline.