An order of actinopterygian fishes in the superorder Ostariophysi with about 2700 species, which ranks second in number only to the Perciformes. Cypriniformes is the largest order of freshwater fishes in the world. Six families of cypriniforms occupy the freshwaters of most of the major landmasses of the world, but are notably absent from South America, Madagascar, and the Australian realm. North America is represented by two native families, Cyprinidae and Catostomidae.