Educational film about the formation and distribution of coral reefs and their inhabitants. On the physical map of the world with the help of MLTP, the places of distribution of corals are shown: in the Atlantic Ocean - the Caribbean Sea, the Gulf of Mexico and the eastern coast of South America, in the Indian Ocean - this is its northern part, in the Pacific Ocean - throughout the entire water area. Photos of various types of coral reefs include atolls, coastal reefs and the Great Barrier Reef along Australia's northeastern coast. Underwater photography of coral reefs and their inhabitants: fish, molluscs, crabs, moray eels, ophiura (snake-tails), octopuses, sea urchins and many others. etc. The scuba diver hides the crown of thorns sea urchin - the main enemy of corals - in a bag. Ruined dead coral structures. Human pollution of water also interferes with coral life.