About Coral Reefs
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Often called "rainforests of the sea", coral reefs form some of the most diverse ecosystems on Earth, housing tens of thousands of marine species. About one-third of all marine fish species live part of their lives on coral reefs.
Coral reefs cover less than 0.2% of our oceans but they contain 25% of the world's marine fish species!
Source: Smithsonian Institution National Museum of Natural History