The molly fish is a species of fish of the genus Poecilia. They inhabit fresh, brackish, salt, and coastal waters from North Carolina to Texas and the Yucatán Peninsula of Mexico.
The body of the sailfin molly is essentially oblong. The head is small and dorsally flattened, with a small, upturned mouth. The caudal peduncle is broad and the caudal fin is large, rounded, and sometimes tipped with black.
The pelvic fins originate at a point anterior to the dorsal fin. In mature males, the dorsal fin is greatly enlarged (it is this feature that gives the species its common name) and the caudal fin is similarly colourful; these conspicuous secondary sexual features play a role in female mate choices. Females tend to be larger and more plainly colored, a different characteristic to the Poeciliidae.
The body is generally light grey, although breeding males may be greenish-blue. Several rows of spots occur along the sides, back, and dorsal fin. Often, these spots blend together, forming stripes. Aquarists have developed many color variations in this species (variation occurs naturally in the wild), with melanistic, leucistic, albino, and speckled forms known.
Source: Wikipedia contributors. (2019, September 23). Sailfin molly. In Wikipedia, The Free Encyclopedia. Retrieved 01:20, October 19, 2019, from https://en.wikipedia.org/w/index.php?title=Sailfin_molly&oldid=917426862