The Robinson Library >> Science >> Zoology >> Fishes >> Class Actinopterygii
Wolf Eel

Anarrhichthys ocellatus (aka northern wolffish, doctorfish)


Despite its name, the wolf eel is not an eel, nor does it look even remotely like a wolf. The "eel" part of its name is explained by its eel-like body, which can be up to 8 feet long, while the "wolf" part refers to it being a member of the wolffish family.

Juvenile wolf eels are burnt to bright orange in color. That coloration changes to gray for males for females and brown for females. Both sexes have spot patterns around the eyes that are distinctive to each individual.

Like many eels, wolf fish have a dorsal fin that stretches from the head to the end of the body. The large pectoral fins have 18 to 24 rays, and the long anal fin has 180 to 230 soft rays. There are no pelvic fins.

wolf eel

The most prominent features of the wolf fish are its robust head and strong jaws capable of crushing shells. Males have thicker jaws, as well as a bulging forehead. The wolf eel's mouth and jaws are so robust, in fact, that they are virtually impenetrable, even to the very sharp spines that adorn the urchins they love to feed on.

Distribution and Habitat

Adult wolf eels live in shallow, cold, coastal waters from the Sea of Okhotsk and Sea of Japan to the Aleutian Islands and along the western coast of North America to Baja California. Although occasionally found as deep as 740 feet, they are most common in sheltered, rocky, sub-tidal areas or near rocky structures in areas with sandy bottoms. Juveniles spend the first two years of the lives drifting before moving into shallow waters.


Adult wolf eels feed primarily on hard-shelled invertebrates, with a particular fondness for sea urchins and crabs, but will also take the occasional fish. These are eaten with the help of conical teeth that hold the prey and huge molars that can easily crush through shells. Juveniles feed almost exclusively on zooplankton.


Wolf eels begin forming monogamous pairs at about 4 years of age. While most mating pairs will stay together for life, it is not uncommon for some wolf eels, both male and female, to change partners fairly abruptly, and some males may even have a "mistress" or two.

Spawning begins in October and continues into December. The female produces up to 10,000 eggs, which are fertilized externally by the male and then "herded" into a mass. The mass does not need to adhere to anything because the parents will take turns wrapping their tails around it, holding and turning it for good aeration. The eggs hatch at 91 to 112 days, at which time parental responsibility ends.

Other Information

Wolf eels remain in their rock crevices during the day and emerge to forage at night. They roam widely looking for prey, but have a great deal of site fidelity, returning to the daytime dens and inhabiting them for long periods of time. Vacated dens are rapidly inhabited by other wolf eels, though, so they may patrol potential den sites regularly. They seem to be territorial, aggressively defending their den area.

Wolf eels swim by making deep S-shapes with their bodies, like a snake moving across the ground.

When threatened, wolf eels approach the threat with the mouth held open, displaying the teeth.

Scientific Classification

phylum Chordata
subphylum Vertebrata
superclass Osteichthyes
class Actinopterygii
order Perciformes
family Anarhichadidae
genus & species Anarrhichthys ocellatus

The Marine Detective

Questions or comments about this page?

The Robinson Library >> Science >> Zoology >> Fishes >> Class Actinopterygii

This page was last updated on June 06, 2017.