is that pinched mantle?

[daniella3d]

an update on the clam. I did 2 freshwater dip at one week interval but it did not do anything. The clam still show some receiding on this area but it is not getting worse.

It seem to be better in the morning and getting worse by the end of the day, so it's wierd. If I cut off a bit of ligth then it seem to improve sometime, sometime not.

This problem has been doing on for a month now, so not sure what it is. I am guessing if it was pinched mantle, it would have got worse?