Gonorynchiformes 37 Cypriniformes 4,501 Characiformes 2,168 Gymnotiformes 239 Siluriformes 3,813 Ostariophysi is the second-largest superorder of fish.

[1] Members of this group include fish important to people for food, sport, the aquarium industry, and research.

[1] Otophysi was coined in 1970 by Rosen and Greenwood to separate the traditional Ostariophysians from the added Gonorynchiformes.

The separation of Laurasia in the north from Gondwana in the south isolated the lineages which gave rise to the modern Cyprinoformes and Characiphysi.

The Characiphysi then was itself divided into the diurnal (day-active) Characiformes and the nocturnal (night-active) Siluriphysi, including Siluriformes and Gymnotiformes.

The Siluriphysi originated before the breakup of Gondwana into South America and Africa in the Aptian (c. 110 Ma) but the presence of several basal Siluriphysan taxa in modern South America (Gymnotiformes, Diplomystidae, Loricaridea) suggest that the Siluriphysi may have originated on the western portion of Gondwana.

It contains one of the largest freshwater fish ever caught, the Mekong giant catfish, which can weigh up to about 300 kilograms (660 lb).

A smaller anterior chamber is partially or completely covered by a silvery peritoneal tunic.

Minute, unicellular, horny projections known as "unculi" are commonly present on various body parts and are only known from ostariophysians.

[1] The ossicles connect the gas bladder wall with Y-shaped lymph sinus that abuts the lymph-filled transverse canal joining the sacculi of the right and left ears.

It is named after the German anatomist and physiologist Ernst Heinrich Weber who first described the Weberian ossicles.