European Brook Lamprey Identification Guide

Key identification features

• Small, slim, eel-like body, usually 10-15 cm long at maturity
• Two dorsal fins that sit close together, often nearly touching, with only a shallow notch between them
• Oral disc present but bearing small, blunt, poorly developed teeth
• Plain grayish-brown to olive back with a lighter underside and no strong blotching
• No paired fins and smooth, scaleless skin, as in all lampreys
• Adults do not feed and live only a short time after transforming from the larval stage

Common look-alikes

• River lamprey is considerably larger and retains strong, functional teeth used to feed on host fish, unlike this species' weak dentition.
• Sea lamprey is much bigger and shows an obviously mottled, marbled body pattern rather than the plain tone of the brook lamprey.

Where you'll see one

This species is widespread across small, clear, gravel- and sand-bottomed streams throughout much of Europe, where larvae burrow into silty margins for several years before a brief, non-feeding adult stage confined to freshwater.