Cypriniformes is an order of ray-finned fish, which includes many families and genera of cyprinid fish, such as barbs, gobies, loaches, botias, and minnows. Cypriniformes is an “order-within-an-order”, placed under the superorder Ostariophysi—which is also made up of cyprinid, ostariophysin fishes. The order contains 11-12 families, over 400 genera, and more than 4,250 named species; new species are regularly described, and new genera are recognized frequently. Cyprinids are most diverse in South and Southeast Asia, but are entirely absent from Australia and South America. At 112 years old, the longest-lived cypriniform fish documented is the bigmouth buffalo.

Loaches are fish of the superfamily Cobitoidea. They are freshwater, benthic (bottom-dwelling) fish found in rivers and creeks throughout Eurasia and northern Africa. Loaches are among the most diverse groups of fish; the 1249 known species of Cobitoidea comprise about 107 genera divided among 9 families.