When to remove dead/dying corals

I have two corals in questionable health. One is a small acropora frag. I wasn't really looking to keep any SPS, but my little yellow clown goby was pissing off all the softies by lounging all over them. Well, he LOVED the acropora, laid on it the moment it was in there and has pretty much left everything else alone. But he's also biting it/eating it. :doh: I believe his picking (probably combined with my inability to keep the tank sterile enough for sps) has caused RTN. It's almost completely white now (almost getting a greenish shade to the bottom). When will I know if it's dead? Will it just fall apart?



Second one is a jasmine polyp. I ordered one from LA, which had aiptasia, and they told me to do a five minute freshwater dip. It's fine and flourishing now. I did the same with this one (not from LA but still with aiptasia) but it's VERY angry. It's been two days and it looks dead. I want to give it a chance to come back, but I don't want it polluting my tank either.



Suggestions? Advice?