Fourhorn sculpin

• Scientific synonym

  Triglopsis quadricornis

(also Myoxocephalus quadricornis)

• Similar species

  alpine bullhead, bullhead, longspined bullhead, short-horn sculpin

• Size

  In lakes 9–15 cm, in the sea reaches 20–30 cm.

• Appearance

  With its large rounded pectoral fins, big rather knobbly head, and protruding lips, the fourhorn sculpin is typical of the Cottidae (sculpins). The sea-dwelling form is best distinguished by the four bony protuberances on the head (absent from the landlocked freshwater form). The freshwater form thus closely resembles the Alpine bullhead and common bullhead, but can be distinguished by its longer caudal peduncle, which is the length of the anal fin. The fourhorn sculpin is the only one of the three to have a separate gill membrane under the head. Also distinguished by the fact that the spiky end of the operculum (gill cover) points straight back instead of curving upwards.

• Colouring

  Upper body dark, mottled. The belly of the female is white, that of the male yellowish brown.

• Reproduction

  Breeding takes place in winter between November and March. The male digs out a spawning bed into which the eggs are released in a single lump. The male attends the eggs, fanning them throughout the 100-day incubation.

• Food

  Bottom-living organisms, fish eggs.

• Distribution and habitat

  Originally a fish of the northern Arctic Ocean. A relict from the Ice Age, the fourhorn sculpin has found its way into Finland’s inland waterways as well as the northern Baltic Sea. Not found in the southern Baltic or North Sea. It avoids water warmer than 10 degrees and thus is not found in shallow waters in summer. As water temperatures fall in the autumn, its range of activity widens. The fourhorn sculpin has no swim bladder, making it a true bottom dweller. Lake form also appears to favour deep water rather than hiding beneath stones along the shore like its cousin the bullhead.