Yucatan Molly Identification Guide

Key identification features

• Large sailfin molly with a deep body and iridescent blue-green base color
• Tall, fan-like dorsal fin bearing 14-19 rays, most dramatic in mature males
• Rows of orange-to-red spots scattered across the flanks
• Rounded caudal fin, sometimes with a hint of extension in large males
• One of the larger mollies, with adults reaching up to about 15 cm

Common look-alikes

• Sailfin molly (Poecilia latipinna): also has a tall dorsal sail but a somewhat smaller one, and it is native to the US Gulf coast rather than the Yucatan Peninsula.
• Shortfin molly (Poecilia mexicana): easily separated by its short, rounded dorsal fin rather than a tall sail.
• Common molly (Poecilia sphenops): smaller body and a shorter dorsal fin lacking the sailfin's dramatic height.

Where you'll see one

Yucatan mollies live across a range of salinities, from fresh to brackish to fully marine coastal habitats, throughout the Yucatan Peninsula of Mexico, often in large surface-schooling groups. They are commonly encountered in coastal lagoons, cenote-fed streams, and mangrove-lined shorelines, where males frequently raise their tall dorsal fins in display to rivals and potential mates.