Believe it or not, millions of tiny delicate coral animals create the enormous coral reefs that can even be seen from outer space. The coral polyps (cnidarians related to anemones and jellies) live in a colony. Together they build a mineral skeleton from calcium carbonate, which creates a complicated reef structure with a myriad of shapes and sizes.
Coral structures provide endless habitats for other animals to live. It’s impossible to talk about corals without talking about the entire reef ecosystem. Coral reefs are the most diverse of any marine ecosystem, often referred to as the rainforests of the sea. A quarter of all marine species depend on coral reefs for food or shelter, or both.