Aquatic predatory bug living mostly in fresh water. When disturbed they dive, carrying with them a supply of air trapped under the wings. They have piercing beaks, used in feeding on tadpoles and small fish.
Females have a sharp ovipositor to pierce the stems of aquatic plants.
Backswimmers fly readily from pond to pond. Four species of backswimmer are found in Britain. The most common is Notonecta glauca found in most British ponds and lakes.