A very common water beetle, 4.5 to 6.3 mm length, it is all brown in colour with the zig-zag ridges on the thorax typical of the genus. Darker spots may be present on the elytra.

It is most similar to H. grandis which is also one of the larger Helophorus beetles. They can be separated by the size and shape of the 'teeth' at the end of the last abdominal segment - small and numerous in aequalis, larger and castellated in grandis.

• 4.5mm - 6.3mm
• intercalary stria present
• elytral margin barely visible from below (not to be confused with the epipleur which is visible)
• 'teeth' on last abdominal segment small and numerous (~15 over 0.5mm)

Helophorus aequalis is nearly always found near water, but not necessarily in it.

All year round, but more readily recorded in summer.

The larvae live in the water and are fierce predators.

Widespread and frequent in Britain.

Common in Leicestershire and Rutland.