It can change the color of its skin in order to avoid enemies, much like a chameleon. Giant Clams also call the reefs there home. If people do not know what a clam is then you need to get a book and find out because I have known what they have been for years. Clams also give us a rare gem. The pearl grows inside of there mouths and is harvested by oyster divers, and clam divers.
Some pearls can get to be the size of golf ball.
Many different species of Crab also claim the reef as their home. In the case of the hermit crab it is the second area they call home. We all know that hermit crabs carry shells that act as homes to them. If they outgrow the shell they will quite simply find a bigger shell to call home. The creatures mentioned above a virtually harmless to humans.