An elongated laterally compressed fish with a dorsal fin that runs along most of the back and reduced or absent pelvic fins. It occurs in cool inshore waters of the northern hemisphere.
- Family Pholidae: two genera and several species
- Not eels at all, the wolf eel are among the largest of a sub-order of small gunnels and blennies.
- The butterfish, also known as the gunnel, is another species quite closely related to the blennies, though again not in the true blenny family.
late 17th century: of unknown origin.