Neon Butterfly Balloon Molly Regular Poecilia Mollies are very closely related to the guppies, and are both members of the same genus, Poecilia. Also included in this genus are the platys. Most mollies that are sold are found in Central America and southern part of the United States. They can be found as either shortfin or sailfin mollies. The shortfin are smaller and the sailfin are bigger. Male mollies have larger dorsal fins than females. Shortfin mollies: