This article states on what corals are, what their anatomy is, how they feed, ...
Anatomy[edit | edit source]
Coral polyps are extremely fragile, and can easily be killed if touched. When threatened, they retreat into their limestone skeleton for safety.
Coral Polyp: The soft fleshy part of a coral that extends out of the limestone cup or coral skeleton. Viewed closely, they may appear as “hair” or tiny flowers on the coral. Divers and snorkelers should never touch or handle a coral unless absolutely necessary. If it is necessary to handle a coral it is very important to make sure all of the polyps have retracted into their skeleton before touching the coral. This can be accomplished by gently fan above the surface of the coral with your hand without actually touching the coral.