What is the significance of coelenterates in nature?

Intestinal can serve as food for other types of organisms, that is, participate in food chains. Marine species purify water from harmful impurities, can form coral reefs (atolls and madrepore corals), are sedimentary rocks used in the production of building materials. Also, some species are used as food and raw materials in the cosmetic and pharmaceutical industries, for laboratory research. There are coelenterates – parasites of fish, can be poisonous to humans and other animals.