octocorallids

Octocorallia is a subclass of Anthozoa, which are marine invertebrates in the phylum Cnidaria. Octocorallians are commonly known as soft corals. Unlike their hard coral relatives, octocorallians do not secrete a large external skeleton of calcium carbonate. Instead, they possess a skeleton composed of tiny, calcareous spicules embedded in their soft tissues, and some also have an internal axial skeleton of fused spicules or a proteinaceous material called gorgonin. This subclass is characterized by polyps that have eight pinnate (feather-like) tentacles. These polyps are typically colonial, with individuals interconnected by a coelenteron, the internal cavity.

Octocorallians exhibit a wide variety of forms and habitats. They can be found in all the world's oceans, from shallow tropical reefs to the deep sea. Common examples include sea fans, sea whips, sea pens, and soft corals like Gorgonians. Their colors range from vibrant hues to more muted tones, often due to symbiotic algae or pigments within their tissues. Octocorallians are sessile, meaning they are attached to a substrate, and they are suspension feeders, capturing plankton and other small organisms from the water column using their tentacles. They play important roles in marine ecosystems, providing habitat for other organisms and contributing to biodiversity. Reproduction can be sexual, with broadcast spawning or brooding, or asexual through budding or fragmentation.