Hi Dr. Mac, hoping you can share some of your expertise regarding clams and what is commonly called Pinched Mantle. Their is information going around that pinched mantle (the symptom) is caused by a protozan. I have suspected it is just a clam that is not healthy from either tank conditions or shipping stress or someother aliment like pyramid snails etc... With your experience do you have any insight into this? Do you think it is a protozan/bacteria or general health/tank conidtions. If it is a protozan/bacteria and not a environment issue is it treatable?