Poeciliidae

Usumacinta molly

Poecilia kykesis

Males display enlarged dorsal fin

• Tropical
• Regional distribution
• Central America and the Caribbean
• North America
• Compressed cross-section
• Small
• Tropical fish

Poecilia kykesis, also known as the Usumacinta molly, Petén molly, spiketail molly, or swordtail molly, is a poeciliid fish species native to the fresh and brackish waters of Mexico, Guatemala, and Belize. It belongs to the sailfin molly clade, with males exhibiting an enlarged dorsal fin. The species has a complex and controversial naming history, with the former name, Poecilia petenensis, now referring to a short-finned molly species.