Corals are small colony-forming marine invertebrate animals. Coral colonies are composed of these tiny, cup-shaped animals called polyps, which are related to jellyfish. Corals begin life in tropical waters as free-floating larvae. After a relatively short period of time, the larva eventually attaches itself to a hard surface and becomes a polyp. Polyps divide and form colonies.
Corals extract calcium and carbonate from seawater to build an inner skeleton that is external to the coral. This external skeleton lies underneath a thin layer of tissue. Over the years millions of coral polyps in colonies create the framework of the coral reef. Coral reefs grow very slowly. These coral reef are very colourful and attractive. The colour, shape ordesign of coral reefs vary according to the coral-genus that produce the reef.
Deepwater and shallow water coral reef communities are rich in diversity and provide habitat for many species.