Length 3.5 to 4.5 mm rove beetle. It is dark grey with some yellow on the antennae. Stenus oscillator is almost identical, but very unlikely to occur in Leicestershire and Rutland.

Found in wetlands, in richly vegetated areas besides lakes and rivers and in floodplain fens.

All year round, especially in summer.

Widespread and fairly frequent in Britain.

Fairly frequent in Leicestershire and Rutland.