Water Measurer

Hydrometra stagnorum

  1. Wildlife
  2. Invertebrates
  3. Bugs
  4. Water Measurer


The Water Measurer (or 'Common Water Measurer') is a long-legged, thin, brown bug that lives on the surface of the water and around the edge of ponds and marshes. A scavenger and a hunter, it feeds on small insects that float to the surface, whether dead or alive. It is very sensitive to vibrations on the surface of the water, using them as a way to locate prey such as mosquito larvae. It spears its prey with its mouthparts and sucks the contents out of the body.

How to identify

Much more fragile-looking than the similar Pond Skater or Water Cricket, the Water Measurer is more likely to be found on stagnant water or bare mud.

Where to find it



When to find it

  • January
  • February
  • March
  • April
  • May
  • June
  • July
  • August
  • September
  • October
  • November
  • December

How can people help

Human activity, including the drainage of land for agriculture and the loss of ponds through development, has resulted in the disappearance of many wetlands. The Wildlife Trusts are working closely with planners, developers and farmers to ensure our wetlands are protected. You can help too: encourage all kinds of insects from Water Measurers to dragonflies into your garden by having a wildlife-friendly pond. In turn, they'll provide vital food for other creatures such as frogs and toads. To find out more about encouraging wildlife into your garden, visit our Wild About Gardens website: a joint initiative with the RHS, there's plenty of facts and tips to get you started.

Species information

Common name
Water Measurer
Latin name
Hydrometra stagnorum
Length: 0.9-1.3cm
Conservation status