Anemones will go through cycles of expansion and contraction, where they will puff up very large, and then shrink down to almost nothing. This is their way of balancing internal water chemistry and flushing
wastes out of their system. Some anemones will expand and contract as often as once a day, but anything more than this is a sign that something is annoying the anemone. For the most part, the anemone should remain fully inflated almost all of the time, and definitely during the daylight hours when the light is brightest. If an anemone spends too much time contracted, there is something bothering it. Hope this helps.