Sealife guideAnthozoans: the colorful architects of the seaThe marine cnidarians

Last updated on 09/08/2025 at 11:26 PM

Taxonomy

Embranchement: Cnidarians
Classe:

Nom commun: Anthozoans
Nom scientifique: Anthozoa

Les anthozoaires avec la gorgone rouge

Description

Anthozoans refer to the class of cnidarians, which notably includes sea anemones, corals and gorgonians.

The name anthozoans comes from anthos, meaning flower and zoon, meaning animal.

Anthozoans are animals that appear in the form of a polyp, which is a sac-shaped body whose inner cavity functions as a stomach. This cavity has a single opening to the outside that serves as both mouth and anus. Around this opening, a series of tentacles covered with stinging cells, called cnidoblasts, are present.

The number of tentacles allows the class Anthozoa to be divided into two main subclasses:

members of Octocorallia, which exhibit eight-fold radial symmetry
and members of Hexacorallia, also sometimes called Zoantharia, which exhibit six-fold radial symmetry

Geographic distribution

Anthozoans are found throughout the world's oceans, from warm tropical waters to temperate regions and even near polar areas. Corals are mainly concentrated in tropical and subtropical zones, where they form abundant and colorful reefs, while sea anemones occur in more varied habitats, ranging from shallow rocky coasts to deeper seabeds.

Habitat

Anthozoans can live solitary, like sea anemones, or in organized colonies, like corals. They are benthic animals, attached to the seabed or other surfaces.

Diet

Anthozoans, whether corals or sea anemones, feed mainly by filtering small marine organisms from seawater, such as plankton, crustacean larvae, or tiny fish. Their tentacles, equipped with stinging cnidocytes, allow them to capture and immobilize prey before directing it to the central mouth.

Additionally, many corals live in symbiosis with photosynthetic algae called zooxanthellae, which provide a significant portion of their energy through photosynthesis. This dual feeding strategy, active capture and symbiosis, contributes to their rapid growth and the formation of reefs rich in biodiversity.

Discover Anthozoans

Acropora pulchra coral
(Acropora pulchra)

Cylinder anemone
(Cerianthus membranaceus)

Elkhorn coral
(Acropora palmata)

Magnificent sea anemone
(Radianthus magnifica)

Purple gorgonian
(Paramuricea clavata)

Slimy sea plume
(Antillogorgia americana)

Staghorn coral
(Acropora cervicornis)

Yellow encrusting sea anemone
(Parazoanthus axinellae)

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