Gonorynchiformes

The Gonorynchiformes are an order of ray-finned fish that includes the important food source, the milkfish (Chanos chanos, family Chanidae), and a number of lesser-known types, both marine and freshwater.

The alternate spelling "Gonorhynchiformes", with an "h", is frequently seen but not official.

Gonorynchiformes have small mouths and no teeth. They are the sole group in the clade Anotophysi, a subgroup of the superorder Ostariophysi. They are characterized by a primitive Weberian apparatus formed by the first three vertebrae and one or more cephalic ribs within the head. This apparatus is believed to be a hearing organ, and is found in a more advanced and complex form in the related cypriniform fish, such as carp. Also like the cypriniforms, the gonorynchiforms produce a substance from their skin when injured that dissolves into the water and acts an alarm signal to other fish.