Corals are formed by the accumulation of shells secreted by corals. Shallow water can get more sunlight and have suitable temperatures, which are good for the growth of algae, thus providing more oxygen to the polyps. Therefore, corals generally grow in warm shallow waters.

Corals are formed by the accumulation of shells secreted by corals. Shallow water can get more sunlight and have suitable temperatures, which are good for the growth of algae, thus providing more oxygen to the polyps. Therefore, corals generally grow in warm shallow waters.