structural:reformatting
Systematics

Historically, these included all the forms now placed in the superorder Ostariophysi except the catfish, which were placed in the order Siluriformes. By this definition, the Cypriniformes were paraphyletic, so recently, the orders Gonorhynchiformes, Characiformes, (characins and allies), and Gymnotiformes (knifefishes and electric eels) have been separated out to form their own monophyletic orders.

The families of Cypriniformes are traditionally divided into two suborders. Superfamily Cyprinioidea contains the carps and minnows (Cyprinidae) and also the mountain carps as the family Psilorhynchidae. In 2012, Maurice Kottelat reviewed the superfamily Cobitoidei and under his revision it now consists of the following families: hillstream loaches (Balitoridae), Barbuccidae, Botiidae, suckers (Catostomidae), true loaches (Cobitidae), Ellopostomatidae, Gastromyzontidae, sucking loaches (Gyrinocheilidae), stone loaches (Nemacheilidae), Serpenticobitidae, and long-finned loaches (Vaillantellidae).

Catostomoidea is usually treated as a junior synonym of the Cobitoidei, but it could be split off the Catostomidae and Gyrinocheilidae in a distinct superfamily; the Catostomoidea might be closer relatives of the carps and minnows than of the "true" loaches. While the Cyprinioidea seem more "primitive" than the loach-like forms, they were apparently successful enough never to shift from the original ecological niche of the basal Ostariophysi. Yet, from the ecomorphologically conservative main lineage apparently at least two major radiations branched off. These diversified from the lowlands into torrential river habitats, acquiring similar habitus and adaptations in the process.

The mountain carps are the highly apomorphic Cyprinidae, perhaps close to true carps (Cyprininae), or maybe to the danionins. While some details about the phylogenetic structures of this massively diverse family are known – e.g. that Cultrinae and Leuciscinae are rather close relatives and stand apart from Cyprininae – no good consensus exists yet on how the main lineages are interrelated. A systematic list, from the most ancient to the most modern lineages, can thus be given as: