The wolf eel is a fish with a misleading name and a face only a diver could love. It’s long and eel-like, which is where the “eel” comes from, and it has big canine teeth, which explains the “wolf”. But it’s neither: it’s a wolffish, a relative of the Atlantic wolffish, and it’s famous among cold-water divers for being gentle, curious and loyal to its den and its mate. This guide defines the wolf eel, explains how it differs from true eels, and answers the usual questions about whether it’s dangerous.

Wolf eel defined: a wolffish, not an eel

Same shape, different family tree.

True eels belong to the order Anguilliformes: morays, congers, garden eels, snake eels and freshwater eels. The wolf eel belongs to the family Anarhichadidae, the wolffishes, a small family of cold-water fishes from the North Atlantic and North Pacific. Its closest relatives are the Atlantic wolffish, the spotted wolffish and the Bering wolffish, all heavy-headed fish with big teeth that live on rocky bottoms. The wolf eel is the one member of the family that evolved a very long, tapering body, and that’s why it ended up with an eel’s name. We cover its Atlantic relative on our wolffish page.

You can tell a wolf eel from a true eel in a couple of ways. It has pectoral fins and a long dorsal fin supported by spines, and it has a large, blunt head with thick lips and big, peg-like teeth. It lacks the tube nostrils and pointed snout of a moray. It’s one of several animals that share the eel name without being eels; others include the electric eel, the rice field eel and lampreys. Our page asking is an eel a reptile covers more of the confusion around eels.

What does a wolf eel look like?

The juveniles are bright orange; the adults look like wise old men.

Adult wolf eels are grey, brown or olive, with dark spots ringed in lighter colour on the body. The body is long and compressed from side to side, tapering to a pointed tail, and it can reach about 2.4 m and roughly 18 kg. The head is large and blunt. In older males especially, the face becomes swollen and lumpy, with heavy jowls and thick lips, which gives them the wrinkled, grandfatherly look that divers love. Females tend to have smoother, darker faces.

Juveniles look completely different: they’re orange to rusty brown, with dark spots, and they spend their first year or two drifting and swimming in open water before they settle on the bottom and take on adult colours. Divers who spot a long orange fish in midwater in the Pacific Northwest are often looking at a young wolf eel.

Where wolf eels live

Rocky reefs and crevices along the North Pacific rim.

Wolf eels are found from the Sea of Japan and the Russian coast across the Aleutians and Alaska, and south along the coasts of British Columbia, Washington and Oregon to southern California. They’re most common in the cold, rich waters of the Pacific Northwest, especially Puget Sound and the coast of British Columbia, where kelp forests and rocky reefs give them plenty of dens. They live from shallow subtidal water down to roughly 225 m. They’re not truly a deep-sea fish, despite searches for a “deep sea wolf eel”; most divers see them in 10 to 30 m of water.

Adults pick a cave or crevice in a rocky reef and stay there for long periods, sometimes years. A pair will often share the same den, with their two heads poking out of the entrance side by side.

What do wolf eels eat?

Hard-shelled animals that most fish can’t handle.

Wolf eels are shell crushers. Their jaws carry strong canine teeth at the front for grabbing and broad, molar-like teeth further back for grinding, and the jaw muscles are very powerful. They eat crabs, sea urchins, clams, mussels, snails, sand dollars and some fish. Sea urchins, spines and all, are a favourite, and wolf eels are among the few predators that regularly eat them. That gives them a role in kelp forest ecology, because unchecked sea urchins can graze kelp forests down to bare rock, a job they share with sea otters further north. For comparison with true eels, see what eels eat.

Mating for life and guarding eggs

Wolf eels are devoted parents, unlike true eels.

Wolf eels are thought to form long-lasting pairs once they mature, which takes several years. In autumn or winter the female lays a mass of eggs, often thousands of them, which the male fertilises. The pair then guard the egg mass in their den. One parent typically wraps its body around the cluster while the other stays close, and they turn and tend the eggs during the long incubation, which lasts around three to four months in cold water. That’s the opposite of true eels, which scatter their eggs in the open ocean and never see their young, as we explain in how eels reproduce.

After hatching, the young drift away into open water, where they spend their first period of life as orange juveniles before settling on rocky bottom.

Are wolf eels dangerous? Do they bite?

They’re gentle with divers, but their bite is serious.

Wolf eels have a reputation among divers for being calm and curious, and some long-lived individuals have become well known at popular dive sites. They don’t attack people. But a jaw designed to crush sea urchins and crab shells can do real damage to a hand, and wolf eels will bite if they’re grabbed, cornered or if fingers end up in their mouths. Anglers who hook them also need to be careful when unhooking them.

Some divers have hand-fed wolf eels for years, and the fish can become accustomed to it. My view is the same as with morays: I wouldn’t do it. Feeding teaches a wild animal to approach people for food, increases the chance of bites, and changes its natural behaviour. Watching a pair of wolf eels in their den is reward enough. Our page on eel bites covers first aid for bites from eels and eel-like fish.

How long do wolf eels live?

A long time for a fish.

Wolf eels grow slowly and mature late, and they’re believed to live for 20 years or more. Individuals have been recognised by divers at the same den over many years. Like many slow-growing, long-lived fish, they’re vulnerable to overfishing, although they aren’t a major commercial target. They’re taken as bycatch in some fisheries and occasionally by recreational anglers. For lifespan comparisons with true eels, see how long eels live.

Seeing a wolf eel

A cold-water diver’s favourite.

The best places to see wolf eels are the dive sites of the Pacific Northwest, especially around Vancouver Island in British Columbia and Puget Sound in Washington, where cold, nutrient-rich water supports dense invertebrate life. Public aquariums along the Pacific coast often keep them too. The dive destinations on my own list are mostly tropical, from the Caribbean to the South Pacific, so the wolf eel is one of those animals I’d plan a cold-water trip around. If you go, look for a pair of heads at the mouth of a rocky crevice, and be patient: wolf eels are often curious enough to come out a little way to look back at you.

Why “wolf”? The teeth up close

The name comes from a mouth full of fangs and grinders.

Open a wolf eel’s mouth and you’ll see where the name came from. The front of both jaws carries large, conical canine teeth that project forward, used to pry and grab hard-shelled prey off rocks. Behind them, and on the roof of the mouth, are rows of broad, rounded teeth that work like molars, crushing shells and urchin tests before the food is swallowed. The arrangement is the same in the Atlantic wolffish, and it’s a classic example of teeth matched to diet: the fish doesn’t chase fast prey, it breaks open slow, armoured prey that few other predators can eat.

Those teeth do wear and break with use. In wolffishes, worn teeth are replaced over time, which lets the fish keep a working set of crushers through a long life of chewing on shells. It’s one more way in which the wolf eel differs from a moray, whose long, backward-curved fangs are designed to hold slippery fish rather than crush anything hard.

Wolf eels and people

From fishermen’s bycatch to aquarium favourite.

Wolf eels have never been a major food fish, although they’re edible and have been eaten locally along the Pacific coast. Today they’re best known as an aquarium and dive-site favourite. Public aquariums from Alaska to California display them, and their long lives and calm temperament make them well suited to that role. Their biggest needs in the wild are healthy rocky reefs and the urchins and crabs those reefs support.