Although snorkeling is a relatively safe sport, there are some precautions that you should take to ensure a wonderful experience.
Coral reefs are the most attractive habitat for fish. However, coral is very sharp and quite fragile. It can easily be knocked off and cut you without you even knowing it until you see your bloodstained legs after returning to the boat.
Sea urchin are another snorkeling hazard that should be watched out for. Sea urchin are small, black spherical creatures that have spines radiating in all directions. Their spines are very sharp and can become embedded in your skin if they are broken off. They also contain mild venom that will cause the wound to swell. Some species of sea urchin are more venomous than others, so stay away from them all.
Other sea creatures to avoid include eels that inhabit cracks and crevices. They can be beautiful to watch, but they do have teeth! On rare occasion, snorkelers can see sharks. However, most varieties of sharks are too small to be harmful and typically live in very deep water.