; subclass Actinopterygii, order Tetraodontiformes)
A small family of fish of the open ocean that have a very peculiar body profile—they seem to be all head and no body. The head and body are very deep, the body short and ending in a tail fin that is no more than a narrow band without a caudal peduncle. The pectoral fins are small, the pelvic fins are absent, but the dorsal and anal fins are long and provide the major locomotory thrust. The largest species, Mola mola (sunfish), may grow to 3 m, reaching a weight of some 1400 kg; the other species are smaller. Probably there are three species, occurring in tropical and subtropical seas.
Subjects: Zoology and Animal Sciences.