What Are Corals?
Corals are actually animals
Corals are related to sea anemones and jellyfish. They even have short tentacles.
Reef-building corals and corals used for jewelry are not the same
So-called precious corals live deep in the ocean and grow very slowly. Reef-building corals, on the other hand, prefer shallow waters and grow at a rapid pace.
Reef-building corals need sunlight
Reef-building corals serve as homes for algae, which photosynthesize and provide the corals with energy in return. The corals cannot survive in waters that are too deep for sunlight to reach.