pinched mantle

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...

Got a gigas clam 2 weeks ago and it looks bothered by something. Already inspected for pyramid snails and anything else growing on its shell, it’s about 7” I feed reef nutrition phyto every 3 days, I have a crocea that’s doing great and growing, haven’t seen any fish pick at it either. Ph: 7.9...

My maxima clam (size ~3") has had what looks to me like pinched mantle since December 13th. I though it might be agitated from the algae growing on its shell so I brushed it off. It doesn't seem to be getting better. What can I do to remedy this? Thanks in advance for the help. Tank Parameters...