I recently got an aquacultured ultra crocea clam about 3 weeks ago. The clam has been doing great however 5 days ago I notticed this one area of the mantle where it appears to curl over a little. The area still fully extends and there is no mucous discharge coming from the clam. To be honest it does not show when the lights ramp up throughout the day only as the clam retracts mor of its mantle at night as the lights ramp down. It honestly looks as through the mantle is almost growing and creating a bigger fold. Im just paranoid and would like some second opinions. Like i said the mantle fully extends during the day and the area is not retracted during the day and there is no discharge noted. I already run carbon but have read that running more carbon is the first step of treatment before resorting to a freshwater dip (which would be my last resort if this is PMD). There are no other areas of the clam that appear out of the ordinary. Appreciate any thoughts and positive advice. I have attached picture below.