Bladderworts plant are Utricularia, a genus of carnivorous plants. There are about 230 species. They occur in fresh water and wet soil as terrestrial or aquatic species. They live in every continent except Antarctica. Bladderworts are cultivated for their flowers, which are rather like those of snapdragons and orchids.
All Utricularia are carnivorous and capture small organisms by means of bladder-like traps. Terrestrial species tend to have tiny traps that feed on minute prey such as protozoa and rotifers swimming in water-saturated soil.
The traps range in size from 0.2 mm to 1.2 cm. Aquatic species, such as U. vulgaris (common bladderwort), have bladders that are usually larger and can feed on water fleas (Daphnia), nematodes, even tiny fish, mosquito larvae and young tadpoles.