Actiniidae is the largest family of sea anemones, to which most common, temperate, shore species belong. Most members of this family do not participate in symbioses with fishes. Three exceptions are the bubble-tip anemone, snakelocks anemone and Urticina piscivora.
Tube-dwelling anemones or ceriantharians look very similar to sea anemones but belong to an entirely different class of anthozoans. They are solitary, living buried in soft sediments. Tube anemones live inside and can withdraw into tubes, which are composed of a fibrous material made from secreted mucus and threads of nematocyst-like organelles known as ptychocysts. Within the tubes of these ceriantharians, more than one polyp is present, which is an exceptional trait because species that create tube systems usually contain only one polyp per tube. Ceriantharians were formerly classified in the taxon Ceriantipatharia along with the black corals but have since been moved to their own class, Ceriantharia.
Aiptasia is a genus of a symbiotic cnidarian belonging to the class Anthozoa. Aiptasia is a widely distributed genus of temperate and tropical sea anemones of benthic lifestyle typically found living on mangrove roots and hard substrates. These anemones, as well as many other cnidarian species, often contain symbiotic dinoflagellate unicellular algae of the genus Symbiodinium living inside nutritive cells. The symbionts provide food mainly in the form of lipids and sugars produced from photosynthesis to the host while the hosts provides inorganic nutrients and a constant and protective environment to the algae. Species of Aiptasia are relatively weedy anemones able to withstand a relatively wide range of salinities and other water quality conditions. In the case of A. pallida and A. pulchella, their hardiness coupled with their ability to reproduce very quickly and out-compete other species in culture gives these anemones the status of pest from the perspective of coral reef aquarium hobbyists. These very characteristics make them easy to grow in the laboratory and thus they are extensively used as model organisms for scientific study. In this respect, Aiptasia have contributed a significant amount of knowledge regarding cnidarian biology, especially human understanding of cnidarian-algal symbioses, a biological phenomenon crucial to the survival of corals and coral reef ecosystems. The dependence of coral reefs on the health of the symbiosis is dramatically illustrated by the devastating effects experienced by corals due to the loss of algal symbionts in response to environmental stress, a phenomenon known as coral bleaching.
Cerithidea is a genus of medium-sized sea snails or mud snails, marine gastropod mollusks in the family Potamididae, the horn snails.
Amphianthus is a genus of sea anemones. It is the only genus in the monotypic family Amphianthidae.
Halcampidae is a family of sea anemones. Members of this family usually live with their column buried in sand or other soft substrates.
Sagartiidae is a family of sea anemones.
Pseudactinia is a genus of sea anemones in the family Actiniidae.
Bunodactis is a genus of sea anemones in the family Actiniidae.
Actinia is a genus of sea anemones in the family Actiniidae. Actinia display a rare form of heteromorphosis in which a cut inflicted on a specimen can develop into a second mouth.
Sagartia is a genus of sea anemones in the family Sagartiidae. The genus was first described by Philip Henry Gosse in 1855 and the image is his painting of several species found in British waters included in his book, A history of the British sea-anemones and corals.
Liponema is a genus of sea anemones, in the family Liponematidae.
Haloclavidae is a family of sea anemones. Members of the family are found worldwide and many live largely buried in soft substrates with only their oral disc and tentacles protruding.
Cerianthus is a genus of tube-dwelling anemones in the family Cerianthidae. Members of the genus are found worldwide. They are predators, scavengers and omnivores.
Haliclystidae is a family of stalked jellyfish in the order Stauromedusae.
Phlyctenanthus australis, commonly known as red anemone or southern anemone, is a species of sea anemone in the family Actiniidae. It grows to a maximum size of 10 cm in diameter. The column is red-brown in colour with blue vesicles covering it. The tentacles are reddish-brown and short, and number up to around 100. This species is found in south Australia, New South Wales, down to Tasmania. This species lives on exposed reefs at depths of between 1 and 35 metres.
Actinostolidae is a family of sea anemones in the order Actiniaria. Members of this family are deep sea species, with some occurring at hydrothermal vents.
Actinostola is a genus of sea anemones in the order Actiniaria. All members of this genus are deep-sea species, with some occurring at hydrothermal vents.
Bolocera is a genus of sea anemone in the family Actiniidae.
Mesacmaea mitchellii is a species of sea anemone in the family Haloclavidae. It is found in the northeastern Atlantic Ocean and the Mediterranean Sea where it burrows in soft sediment.
