My clown used to do that, it really didn't hurt or anything. The problem was that it would startle me more then anything. On more then one occassion I knocked over a few rocks causing a rock-slide. I could have a potentially ended up with a broken tank over it. What I do know is when it looks like she is ready to strike I make a backhand motion towards her and she swims back and nestles in her anemone. I have done this a few times and she doesn't really bother me much anymore. It puts her into defense mode as opposed to offense mode. She doesn't really seems spooked of me either. I know she is just trying to protect her territory, but if I drop a rock into the side of the tank as a result she may not have any territory.
