Squamosa slight mantle retraction

[Henk]

I got this nice Squamosa in January. About 8 inches shell length.
My chelmon took too much interest so decided to keep it in the sump where it has been now a few months. It was placed against the side of the sump. Sump is crawling with pods because I don’t keep fish there apart from a pair of clowns in an anemone.
Few days ago I noticed the side touching the side of sump was not fully extended. Not sure if due to irritation of touching the side of sump (with plenty of pods) or if more is going on. Pinched mantle?

In terms of new shell growth, on the outside of the mantle I do not see any. But if mantle is further retracted seems like a new layer of shell is coming up from the inside. Not sure if this is normal for a clam of this size? It gets a lot of light. Placed around 30cm under a Philips coral care (50% intensity with whitish light).

Here some photos, apologies for poor picture quality difficult to get good pics due to where it is positioned.

just keep an eye on it for now?

 

[fishguy242]

@OrionN ? TIA

 

[minus9]

That doesn't look like PMD to me, but something irritating the mantle. If you're not seeing enough growth on the shell, then I think you need to give it more light. I also would move it directly under the light instead off to the edge/side, if you can? You might have to check at night and see if the amphipods are bothering it? It's hard to tell in the mantle if folded over/down or if there's an actual piece missing?