Knowra Sea anemone Sea anemone A predatory marine invertebrate in the order Actiniaria, with a cylindrical body and tentacles surrounding its mouth. It is a close relative of corals and jellyfish.
Cnidocyte : A specialized cell that ejects a microscopic capsule to capture prey or deter threats. Cnidocytes on the tentacles deliver the stings that subdue prey.
Cnidaria : A phylum of aquatic animals characterized by stinging cells and radial body plans. Sea anemones belong to this phylum, alongside corals, hydroids, and jellyfish.
Clownfish : A group of Indo-Pacific reef fish that live among the tentacles of sea anemones. Clownfish gain shelter from predators while anemones may benefit from cleaning or food scraps.
Coral : A marine cnidarian, often colonial, whose polyps may secrete a calcium-carbonate skeleton. Corals and anemones are both anthozoans, but most anemones lack a massive external skeleton.
Nematocyst : A pressurized capsule inside a cnidocyte that fires a coiled, often toxin-bearing thread. This capsule is the projectile sea anemones use to sting prey.
Anthozoa : A class of cnidarians that includes corals and sea anemones, with no free-swimming medusa stage. Actiniaria is an order within this class, whose members live only as polyps.
Hermit crab : A decapod crustacean that commonly shelters its soft abdomen in an empty shell. Some hermit crabs carry anemones on their shells, gaining defense from their stinging tentacles.
Jellyfish : A common name for free-swimming cnidarians, especially the medusa stage of their life cycles. Unlike the familiar medusa form, sea anemones remain polyp-shaped throughout their lives.
Actinopharynx : The muscular throat-like passage connecting a cnidarian's mouth to its internal cavity. Food passes through this passage from the mouth into the anemone's gastrovascular cavity.
Polyp (zoology) : A sessile or slowly moving, tube-shaped cnidarian body form with a mouth surrounded by tentacles. The sea anemone is a large, solitary polyp rather than a jellyfish-like medusa.
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