During my visit to the island, the most unexpected surprise for me was snorkeling at night. Unfortunately, I didn’t stumble across it until the last night of my trip, so I didn’t get a chance to really explore it very deeply.
I highly recommend it to anyone heading to the island. There are a lot of creatures that only come out at night, and it can be easier to “sneak” up on them and catch them unawares. Corals open up like flower gardens with shrimp scampering about them like honeybees. Anyone who has snorkeled at night will tell you that it is an entirely different world beneath the waves at night.