A small (2.6 to 3.2 mm) brown beetle.  

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.

Found in ponds and pools.

Can be encountered in most months.

Widespread and fairly frequent in Britain.

Fairly frequent in Leicestershire and Rutland.