The Flag Platy is a selective breeding form distinguished by its characteristic high dorsal fin, which resembles a flag or a sail in shape. The fish's body is rhomboid, laterally compressed, with a relatively small head. Its coloration is extremely variable: red, yellow, golden, black, marbled, and other color morphs are found. Adult females are usually larger than males, reaching 5–7 cm in length. Males are smaller and easily distinguished by their gonopodium — a modified anal fin that serves as an organ of fertilization.