Viviparous eelpouts grow to a maximum length of 52 cm (25 in) and a maximum weight of 510 g (1 lb 2 oz). They typically live at water depths up to 40 m (130 ft). The fish live to a maximum age of 10 years.
These eelpouts live in a temperate climate in the marine waters of the Northeast Atlantic including the seas such as the Baltic, Barents, Irish, North, and White Seas. They also live in some brackish inlets, such where the River Somme meets the English Channel. The fish stay towards the rocky shorelines and tidepools among the stones and algae. The fish are capable of living out of water under rocks and seaweed due to their ability to breathe air directly. The fish eat eggs and fry of fish and macroinvertebrates such as gastropods and crustaceans.
The fish are notably viviparous, giving birth to 30-400 live developed young. They mate during the months of August and September using internal fertilization.