Crystal Bay was one of my two dives today, the other being Manta Bay, also in Nusa Penida.
Nusa Penida is a small island off the southeastern coast of Bali.
Crystal Bay featured drastic temperature changes because of currents and surges. From hot to cold to hot, and back to cold, all in less than one minute. This continued for the entire dive.
It was only myself and a guide, who ran out of air before I did, which meant we had to cut the dive short. Poor planning on his part, but he was otherwise a fantastic guide: enthusiastic, and he even did magic tricks during the 45-minute boat ride to Nusa Penida. At one point during our dive, he turned to me, pointed to his fins, on which he had written MAGIC, and smiled.
During the dive we saw a school of baracuda, a large puffer fish, an exceptionally large moray eel poking its head out of the massive wall of coral, and thousands of glass fish schooled underneath a mound of coral that resembled a mushroom. The mushroom was maybe five meters high, and it looked as though it belonged in Super Mario Bros. The school of glass fish was not visible until I descended all the way to the sandy bottom and turned my body parallel to the ocean floor.