Sea anemones in a zoo aquarium (England)
The sea anemone is an animal that lives in the ocean. Closely related to coral and jellyfish, the anemone is a (usually) solitary polyp with stinging cells (cnidocytes) in its tentacles. These stinging cells serve to paralyze and capture prey, which is then moved by the tentacles to the mouth for digestion inside a central cavity.
Anemones are classified as cnidarians (Phylum: Cnidaria, Class: Anthozoa, Subclass: Zoantharia). Most solitary anemones are included in the Class: Actinaria. Exceptions are the solitary, tube-dwelling cerianthids (Class: Ceriantharia). All anemones are marine; Freshwater cnidarians that resemble them (called hydras) are included in the Class: Hydrozoa.