2-3cm Black platy. Water quality:Water temperature will need to be between 21° - 27°C with a pH of 7 - 8. Compatability: They make an excellent fish for a community tank given their peaceful nature. Diet: Omnivore. A varied diet consisting of flakes, live and frozen foods will be required optimum health. Platy fish are small tropical fish from the rivers of Central America. Platys are also easy to breed and are live bearers but for the small fry to survive they will need to be separated as other fish in the aquarium will eat them.