Wild populations of these fish exhibit an astonishing variety of coloration, and sometimes morphological differences in fin and body shape. Scientists often debate the reasons for such variations: whether they are the result of adaptation to ecological conditions, hybridization, or manifestations of sexual dimorphism. For example, young males have less vibrant coloration compared to adult specimens. Additionally, the intensity of coloration can be linked to social hierarchy within the group: dominant individuals usually have more saturated colors, while those of subdued fish become duller. Adult members of the species reach a length of about 7 cm. Males have a silvery body with emerald speckles, and their caudal and dorsal fins are colored in orange-red tones with black spots. Females have similar body coloration, but their fins lack color. The history of the Free Molly in aquaristics began in 1935, but at that time, suitable conditions for its keeping could not be provided. Over time, from generation to generation, the fish's coloration faded, and soon colorless specimens lost their appeal to aquarists. Currently, the Free Molly is once again gaining popularity.