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Corals are reef-building organisms that usually live in groups of related individuals called colonies. They can have hard stony skeletons, or softer, more leathery exteriors.
The stony coral has a cup-like skeleton that is made of sturdy calcium carbonate. At night its tentacles extend, capture food, and carry it to the mouth. The coral also gets nutrients from algae that live in its body and make food from sunlight.
Some corals have softer skeletons and more complex lobed or branched forms. These soft corals gather on the reefs created by stony corals. | |
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