So I finally dove into my tank with a mask and snorkel to start taking things out that were out of control. I snapped out a bunch of monti cap, some of which had grown onto a brain coral. When I did that, i was near my clam. He has been super happy with no issues in two years. I got home yesterday and saw him gaping with his mantle retracted. Could sand or monti-slime have done this? Thought they were a little hardier than this...