We have gone on night snorkels with Tulu the past two years, it is really an awesome experience. Eels, octopus, lobsters, trunk fish (really fun), both times we saw lemon sharks but they run away from the light. It is kindof cool when their are divers below you or coming toward you with their lights, kindof twilight zonish. This last time it was almost a full moon, so you could see even without lights the water is so clear, but you see more night creatures if it's darker.