Never frag an anemone. You can, not many people have though. Fragging an anemone basically is causing the specimen major stress causing it to split. By this, if you are lucky, you may end up with 2: mother piece and its clone. If you don't get that lucky, you end up with a dead anemone. I wouldn't recommend doing this.
If you still want to go ahead and do it, try the clown and anemone forum, they may have more information than I do on this topic. I think the 'stressing the anemone' out has to do with cutting the light period down or try moving it or doing other things that they don't like.