A small (3.2 to 3.8 mm), dark coloured water beetle. Female prosternum with sharp median keel.

Unless identified by a recognised expert, a photo is required and the specimen should be examined with a microscope. In the comments box, state the key or ID method used and describe the size and identifying characters.

Most often encountered around pools and ponds, but may be seen at the margins of any water body and also attracted to light.

April to October.

Widespread and common in Britain. 

Common in Leicestershire and Rutland.