Every little polyp is a separate animal. I started with little tiny pieces and they've grown in the tank. The tongue coral has tentacles that come out occasionally. The brain coral swells overnight and is most beautiful in the morning. The later in the day it gets, the more it closes down.
Most corals have a sting, harmless to humans, which can damage or even kill encroaching neighbors.
That one is pretty hot, but they're not all the same. Some are hotter than others. Williams said it is not difficult to keep the aquarium, but attention to detail is important. The creatures' greatest needs are light, oxygen and moving water. In Williams' tank metal halide and very high output bulbs total 400 watts.