A very small (2 mm) riffle beetle that is equipped with strong claws to enable it to grip in strong currents. It is a dark coloured species with very deeply ridged elytra.

It is a water beetle of running water, but cannot swim and lives amongst stones, moss and algae.

Late summer and autumn are the peak time.

It does not need to surface for air as it breathes the trapped oxygen in submerged bubbles but it does leave the water at times and can fly.

Widespread and common in Britain.

Quite common in Leicestershire and Rutland.