How large is your ball anemone? The reason I ask is because there are basically two varieties: the large Caribbean variety, and the rather small Pacific variety.
I have a large orange-ball anemone (Pseudocorynactis, Caribbean) in my tank. It gets fed every night and is a huge eater. It never moves from its rock, and I don't think they ever do. With good feeding, they will eventually split. They can also be fragged extremely easily from what I've heard. The major problem with them is that they can be very greedy and go after mobile inverts and even fish. If you feed them well, this doesn't seem to occur. This is really only a problem with the Caribbean variety, as the Pacific ones only get to like half an inch.