corals are invertebrate animals belonging to a large group of colourful and fascinating animals called cnidaria other animals in this group that you may have seen in rock pools or on the beach include jelly fish and sea anemoneshere are around 800 known species of hard coral also known as the reef building corals soft corals which include seas fans sea feathers and sea whips don t have the rock like calcareous skeleton like the others instead they grow wood like cores for support and fleshy rinds for protection