 The larvae are called bloodworms because some larva are bright red, but they can also be found in brown and almost black.When the larva pupate, they drift towards the surface, making them vulnerable to many types of fish.Other common predators include the common backswimmer ("Notonecta glauca"), common pondskater ("Gerris lacustris"), common toad ("Bufo bufo"), lesser water boatman ("Corixa punctata"), dragonflies, damselflies, great crested newt ("Triturus cristatus"), great diving beetle ("Dytiscus marginalis"), redstart ("Phoenicurus phoenicurus"), smooth newt ("Triturus vulgaris"), water scorpion ("Nepa cinerea") and other midges such as "Anatopynia plumipes".