Great Diving Beetle (dytiscus marginalis)

This is one of the biggest insects in our pond. They can grow up to 3cm long, and they are definitely carnivores. In fact, they have a reputation for eating anything and everything in ponds! 

Look out for them if you are observing a pond. They store air under their wings, so sometimes you will see them come to the surface and stick the back of their wings above the surface to refill this air store.  

They can also fly. Sometimes at night time they fly to other ponds to start breeding there.