Wolf fish, Catfish Anarhichas lupus

This fearsome-looking fish is not as aggressive as it looks - it will not attack unless provoked, and its fangs are used for gripping and crushing the shells of creatures it eats. With its large, blenny-like head, bulging eyes and thick, tapering eel-like body, an adult wolf fish can grow to around 120cm long and weigh more than 20kg. Its thick grey skin is often wrinkled, and there are often scars on its face from encounters with crabs and other prey.

Where does it live?

A colder-water fish, this species occurs all around Britain, but we only see them regularly in relatively shallow water on the Scottish east coast and in north east England. It is common in Scandinavian fjords and occurs in deeper water down to 450m as far south as the Bay of Biscay.

On rocky seabeds wolf fish use a large crevice or space beneath a boulder as a lair, often occupying a suitable hole for a long time. One wolf fish named George became a well-known attraction for divers at St Abbs for many years, being easily found in the same hole at only 10m. St Abbs is still considered the best place in the UK to see them. Wolf fish also inhabit sediment seabeds, especially if there are scattered rocks for shelter. Young fish may shelter in kelp forests.

How does it live?

A wolf fish's lair is often easy to spot, surrounded by the remains of its meals - the shells of molluscs, crabs and urchins. As well as its long fangs, the wolf fish has teeth embedded in its palate, helping it to crush hard-shelled prey. The fish spawn in winter, laying clumps of yellow eggs under stones or overhangs, and the male fish guards these for 2 to 3 months until they hatch. During this time the father tries to intimidate potential predators - divers report that he will puff himself up and click his teeth if they approach too close! The larvae drift for some time in deep water at 100-200m before taking up life on the seabed. Wolf fish take 6 to 7 years to reach spawning age, and are thought to live for around 20 years.