Hydra and Daphnia

Hydra is a minute predaceous carnivore in the Phylum Cnidaria (along with jellyfish, sea-anemones and corals). They paralyze their prey with a harpoon-like stinging apparatus called a cnidocyte. Daphnia (sometimes called a “water flea“) is a planktonic crustacean. Although both animals are common in freshwater ecosystems locally, these were purchased from a biological supply company and photographed in a small aquarium in Ohio, USA, on February 17, 2011.