How many ostariophysan species are recognized?

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knifefish — ostariophysan Knifefish, or featherback (Xenomystus nigri)

There are approximately 8,000 recognized species of ostariophysans, a group that comprises nearly one-fourth of all known bony fishes.12

These species are classified within the superorder Ostariophysi, which includes the majority of the world's freshwater fishes. The group is divided into five orders:13
* Siluriformes (catfishes): 2,867 species3
* Cypriniformes (minnows, carps, suckers): 3,270 species3
* Characiformes (characins, hatchetfishes, pencil fishes): nearly 1,700 species3
* Gymnotiformes (electric eels, knifefishes): 134 species3
* Gonorynchiformes (milkfish, beaked sandfishes): 37 species3