While male and female platy fish can live in an aquarium together, responsible fish owners should know the difference, especially if they want to reduce or eradicate breeding.
Platy fish come in a variety of colours and hybrids. Some include red, calico, red and gold wag, Mickey Mouse and spotted platies in various colours. No matter what the type, you can tell the male from the female in the same way.
Identifying male and female platy fish is a matter of looking closely at their bodies. A male fish has a elongated gonopodium, which is a protuberance near the anal fins used to transfer sperm to the female.
Platy females are larger than males. Not only are they larger as they grow, but they reach a greater adult size. Females may grow to 2.5 inches long, while males top out at 1.5 inches.
Platies are livebearers, so they will procreate rapidly, overwhelming your aquarium. Select only one sex of fish, or purchase a much smaller number of males than females.
Keeping too many male platy fish with too few female platy fish can lead to stress, as the males constantly chase the females to breed. This stress can lead to fish death or unhealthy fry, which are baby fish.