| Correct me if I'm wrong, but I dont think there would be a real issue w/ just leaving it on the shell. I cant remember, but I dont think that pocilliopora corals are all that potent w/ their defenses. Thats why they have adapted to being able to spread so easily and readily as they have. I'd leave it, unless you already see some negative reactions from te clam. The clam will shade certain areas w/ its mantle, and the coral will grow on others. Its not like clams arent found IN corals heads in nature....
JMO
Nick |