is that pinched mantle?

[daniella3d]

I seams to be getting a bit worse today

It's a little bit more receided but only those 2 spots...

how do we call sections of mantle? Like there are 4 sections on each side and only 2 sections on only one side are showing this. The rest of the clam seams top health. The clam react well to light and is not gaping. This is very wierd.

I am debating to do a fresh water dip or not. I don't know what's a fresh water dip could do if the problem is not pinched mantle...

Also something wierd that I have noticed, is that underneat the affected sections, the new growth of shell has some sort of filaments. I checked and it is not something alive, rather it looks like it's the tissue of the shell that is getting soft on the edge.