That's the only way to remove a clam from a rock? I don't want to injure these clams.
Is there some way to make a clam uncomfortable, so they would relax their hold on the rock? Water flow or lighting?
I have a maxima that walked himself into a place he really didn't like and dropped his biassial threads all on his own. I don't know how to force them to do this though, and they would probably have to not like it for a couple of days before they do anything about it.