Cypriniformes: Minnows, Carps

One of the most diverse orders, there are over 3200, found mainly in Southeastern Asia, and no species found in Australia or South America. They differ from most other Ostariophysans in lacking an adipose fin near the tail.


By carolineCCB (Leopard Danio Uploaded by Magnus Manske) [CC BY 2.0], via Wikimedia Commons

Cyprinidae: Minnows, Carps

The minnows and carps are familiar to many as aquarium fish or in ponds. And are the largest vertebrate family with over 3000 living species. They are found in only freshwater. Some familiar species are below.


By Haplochromis (Own work) [GFDL ( or CC BY-SA 3.0], via Wikimedia Commons

Psilorhynchidae: Mountain Carps

Unlike the cyprinids, this is a much smaller genus with much smaller fishes. They have jaws with sharp horny edges, a ventrally flattened head, and a reduced swim bladder.


By Garthhh [GFDL ( or CC BY-SA 3.0], via Wikimedia Commons

Gyrinocheilidae: Algae Eater

There is one genus, Gyrinocheilus, and as you may have guessed, they eat algae. In fact, the mouth has been modified into a sucking organ to attach to rocks. This makes it difficult to breath, so the gill slits have been modified into two openings, one for inhaling and one for exhaling.


By Brian Gratwicke [CC BY 2.0], via Wikimedia Commons

Catostomidae: Suckers

These fishes have thick fleshy lips to form a suction to hang onto rocks, and can grow up to 1m. Although similar to related fishes with suckers, they have a row of pharyngeal teeth which are lacking in the other types.


By Wibowo Djatmiko (Wie146) (Own work) [CC BY-SA 3.0 or GFDL], via Wikimedia Commons

Cobitidae: Loaches

These fishes have a wormlike or fusiform body and have an erectile spine below the eye.

loach loach river

Balitoridae: River Loaches

Nelson defines this group as having three or more pairs of barbels by the mouth, and that's it.