Alcyonacea

Alcyonacea is an order of colonial octocoral cnidarians, including soft corals and sea fans. Its polyps typically have eight tentacles bearing side branches called pinnules.

Octocorallia: Octocorallia is a subclass of cnidarians whose polyps typically have eight pinnate tentacles and eight internal partitions. Alcyonacea belongs to this broader group, which also includes sea pens and blue corals.
Coral polyp: A coral polyp is an individual, soft-bodied cnidarian unit with a mouth surrounded by tentacles. Each alcyonacean colony is built from many polyps that capture food and perform other functions.
Sea fan: A sea fan is a branching, often planar gorgonian coral colony adapted to water movement. Sea fans are conspicuous alcyonaceans whose flattened branches maximize exposure to currents.
Scleractinia: Scleractinia is an order of stony corals that typically builds calcium-carbonate skeletons. Most alcyonaceans lack the rigid, individual corallites characteristic of scleractinian colonies.
Coral aquarium: A coral aquarium is a marine aquarium designed to keep corals and other reef organisms. Some soft corals are kept in aquaria, where their husbandry differs from that of stony corals.
Cnidaria: Cnidaria is a phylum of aquatic animals characterized by stinging cells called cnidocytes. Alcyonaceans are cnidarians, sharing the phylum's basic body plan and stinging-cell ancestry.
Suspension feeding: Suspension feeding is the capture of food particles carried through water. Alcyonacean tentacles intercept plankton and organic particles carried by currents.
Soft coral: A soft coral is a coral lacking the massive external calcium-carbonate skeleton typical of reef-building stony corals. Soft corals are a major group of alcyonaceans, supported instead by tissues and small skeletal elements.
Pennatulacea: Pennatulacea is an order of octocorals known as sea pens, often adapted to soft seafloor habitats. Sea pens share octocoral traits with Alcyonacea but form a distinct order with a different colony organization.
Marine natural products: Marine natural products are chemicals produced by marine organisms and studied for biological activity or practical use. Alcyonacean compounds are investigated for chemical defenses and potential biomedical applications.

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AnthozoaBroader topic: Its varied colonies show that coral forms extend beyond reef-building stony corals.