Platys are one of the several livebearing species of freshwater fish popular with aquarium enthusiasts. Grouped together with their close cousins, the swordtails, platys are part of the genus known as Xiphophorus. They are hardy, compatible with other fish, and are extremely easy to breed. They also come in a variety of attractive colors and forms.
Although platys comprise only a couple of species within the Xiphophorus genus, there are considerable variations in color and even fin-type within these species. Furthermore, the species interbreed so readily that many specimens sold in the trade are mixed hybrids. However, they all do well in similar conditions, so unless your goal is to breed a pure line, this doesn’t really matter. Choose your variety based on whatever appearance you like.