The Sailfin Molly is one of the most easily-identified species of Molly. There are several color morphs that have been selectively bred for the aquarium trade, including black, harlequin, and dalmation. The most distinctive feature of this species – the feature for which it is named – is the enlarged dorsal fin that exhibits a sail-like shape. Sailfin Mollies are native to parts of southern North America and Mexico. They can usually be found in coastal waters, particularly in brackish environments such as swamps and estuaries.