Divers in coral reefs must exercise proper buoyancy control to avoid damaging the fragile growths of coral. Some of these growths are hundreds of years old, and are easily damaged or killed by even the slightest touch.

Another reason to avoid contact with the corals is the potential injury they may inflict on the diver. Corals hunt by injecting stinging cells into their prey. Most of these stings aren't powerful enough to be felt by humans, but a few species are capable of inflicting painful stings that require medical attention. Additionally, most hard corals are sharp, and can cut or scrape the skin.