I have a Maxima clam that is about 2 inches. It use to open up real well. But recently he pulls in part of his mantle like something is iritating it.. He is pulling that part in more and more while it opens the rest of his mantle. I went and got a magnifying glass to see if I could see any of the parasidic snails, All I see are these white spots all over that part of the mantle. It looks like sand stuck to the mantle. I got some of it off and it feels like sand. Do these snails look and feel like sand when they are in the egg stage or when they are babies. I don't see anything moving. I searched the clam all over and found no other trace of anything. All the other clams are still opening great.