Definition:
Corals are animals in the Phylum Cnidaria. Cnidarians also include sea fans, sea pansies and anemones. Corals are in the Class Anthozoa, and can be divided further into the stony corals (Order Scleractinia), the builders of coral reefs, and soft corals (Order Alcyonacea), which are soft or leathery and include species such as bubblegum corals and mushroom corals.
In addition to their contribution to reefs, stony corals differ from soft corals in that the polyps of stony corals have tentacles in multiples of six, while soft coral polyps have eight tentacles.
