The ragfish (Icosteus aenigmaticus) is a ray-finned fish of the northern Pacific Ocean; although classified as a bony fish, its skeleton is mostly cartilage, and the larvae have pelvic fins that disappear as they mature. It is the sole member of the family Icosteidae within the order Scombriformes. although recent catches show no squid beaks but large numbers of jellyfish. Ragfish are rarely seen and little is known about them.

The larvae make a remarkable transformation as they mature; the dorsal fin and anal fin both shrink, and the pelvic fins disappear.

Formerly, adult ragfishes were considered to be a different species, known then as Acrotus willoughbyi.

References

  • Cal Academy checklist report, September 2003 (PDF)