Reef friendly sunscreen or sunblock
Recently silence has discovered that certain ingredients in sunscreen are hazardous to coral reef. Some companies are now producing reef-friendly sunscreen without the dangerous ingredient, so if you plan to spend a lot of time in the water, please think about changing to a reef-friendly sunscreen brand.
Do not walk on or kick coral reef
This one sounds really obvious so you may be surprised to hear that loads of snorkelers are still walking over reef or kicking the corals with their fins. The damage that this does to coral is immense. Not only are they incredibly fragile in structure but even just touching some corals can cause the death of the entire colony. Some coral is also toxic to humans and can cause severe pain, fever and other unpleasant symptoms.
Do not feed the fish or other marine animals
Many snorkel operators feed the fish in order to bring them closer to the snorkelers. Most often the food they offer, like bread or seeds, does not form part of the fish’s natural food source. Hand fed fish are more vulnerable to predators, and a healthy marine ecosystem depends on competition for habitat and food. Also, some creatures bite. Feeding eels, for example, has lead to many a missing finger.
Do not touch animals (not even for photography purposes).
If you see something lovely and want to photograph it, but find that it isn’t in the best position, come back in a while, or wait at the surface and see if it moves. Please do not move nudibranchs and other critters to make for a prettier photo. Many creatures live in well camouflaged environments to prevent predation, and moving them can put them in danger. Also some creatures are poisonous to humans, or can sting. Many such fish are very well camouflaged and you may not notice them until it’s too late. A sting from a stone fish or scorpion fish is incredibly painful and long lasting, and will probably ruin you entire trip. Also “riding” creatures like whale sharks, manta rays and turtles is unkind, dangerous to man and fish and an all round bad idea.