Coral is made out of colonies of polyps. Polyps are tiny tube like creatures. Each polyp has a group of tentacles coming out of its top. When the polyps join with others, they stick together with calcium carbonate. Thousands of polyps are used to make coral, and it can keep building up and growing at a rate of 10 feet per every 1,000 years. Polyps eat by either grabbing food with the sticky substance on their tentacles or by filtering out food from the water. Coral can be formed into many forms. They can be found as branches, fans, brains and flowers. This is what makes coral reefs beautiful. These forms provide a great home for many species.