Whats happening to my corals?

[michika]

The singapore angel has never touched anything in my tank. This RTN business began before the angel was in the tank. The angel didn't touch the clam either. I've watched my tank for many many many hours, and non of my fish touch my corals or clams. Only my tang goes near one particular clam because it likes the algae on one half of its shell.

The running theory about the clam death is that it got dislodged somehow. While it was in the sand my sandsifter star ate it from the bottom up. The star was right NEXT to the clam both times when we'd noticed it had fallen. It was also found beside it when I picked it up yesterday evening and discovered its innards eaten out. I think my other two clams are safe because they are up high enough that the sandsifter can't get to them.

I'm pretty sure its a chemical issue, or sps coral type virus. I wish it was even something simple like redbugs, but I haven't seen any bugs. What happens to the corals is that they are fine when I leave the house, and then when I come back their flesh has peeled away to reveal either green or white skeletons.

If a fish was picking at my corals wouldn't they be going after to polyps persay? All my corals have had their regular polyp extention at the time I last see them, and then they are just gone when I come back. I don't even see the skin flap off either, and its a VERY quick process, within about 3 hours.

Say a fish was picking at my corals, what type of damage or abbrasions would I be seeing?