Octocorallians

Octocorallians are a subclass of Anthozoa, a class of marine invertebrates in the phylum Cnidaria. This group includes soft corals, sea fans, sea whips, and sea pens. Unlike their stony coral relatives, octocorallians do not secrete a hard external skeleton. Instead, they have an internal skeleton made of tiny calcareous spicules or fused sclerites. A defining characteristic of octocorallians is that each polyp has eight pinnate (feathery) tentacles. These polyps are colonial, meaning they live together in interconnected units. The colony's form can vary greatly, from encrusting mats to large, branching structures. Octocorallians are found in all oceans, from shallow tropical waters to the deep sea, and play important roles in reef ecosystems as habitat providers and food sources. They are filter feeders, capturing plankton and small organisms from the water column using their tentacles. Reproduction can be sexual, with colonies releasing eggs and sperm into the water, or asexual through budding or fragmentation. Many octocorallians exhibit vibrant colors due to symbiotic algae or pigments within their tissues.