I have a squamosa now for about 1 1/2 months also laying in the DSB. I noticed what I thought was the foot a white partialy hairy piece for the last 3 or for weeks. Yesterday when I looked at the tank there was the piece sitting on the bottom close but no longer attached . where it was on the clam there was now a small hole in the mantel. The clam has been open all day and looks as healthy as always but I too am worried . For those clam experts out there is this normal if so why do they drop the flesh also will the hole close.