What is "graveldiver"

The graveldivers (Scytalina cerdale) are perciform fish in the genus Scytalina, and the only species in the family Scytalinidae. Graveldivers are small, with snake-like heads (hence the generic name). Their bodies are compact, and lack pelvic fins, with very small pectoral fins. Their range encompasses the coastal area from the Bering Sea to central California.