I have a T. derasa clam that is a fairly new addition to my reef. It is sitting in the sandbed, with a flat piece of rock directly under it. The clam is attached to the rock as soon as I put it in there and is responding to light/shadows and appears to be healthy. Well I just noticed a "spot" on its tissue that seems to have no pigment. Can't really tell what it is, and what can I do to fix it? Or should I not worry about it? I have two other clams (T. crocea and T. maxima) that are doing very well. Just don't know what's happened to my T. derasa. Picture below. The spot is on the left hand side of the clam. Thanks for the help.
