It is outwardly similar to the sailfin molly, P. latipinna, though larger overall and with a higher and longer dorsal fin in males.

Full-grown fish are usually larger than 10 cm (4 in) and large females can reach almost twice this length, though especially captive-bred individuals grow only to the size of sailfin mollies.

Direct sunlight and an ample supply of plant food, such as lettuce, peas, or certain algae, are necessary for optimal health; in subtropical areas, they can be kept outside in unheated tanks in the summer; in temperate zones, backup heating may be necessary.They are euryhaline species.

To transition a molly to saltwater, adjustment time is needed; increase the salt content to match the reef tank over a period of three hours.

This is generally not very successful, and should not be attempted, as purebred Yucatan mollies are often quite hard to find, and hybrids will not have as massive dorsal fins as these.