Tank trouble!!

[Acro]

Hmmmm,Well all I can think of is now is if the clam has died then perhaps the leaching dead animal would kill the corraline below it. How did the clam look up till yesterday? How did the incurrent syphon look? Was it gapeing? The only thing I can remember reading sometime ago is that what you have experienced happens to newly introduced clam. I would still concider 3 months new intro. I would geuss that perhaps the clam was sick to begin with (perhaps unvisable) but the one change put it over the edge. Obviously just speculation.