Just read the sticky but just want to verify that this is PMD? I've had the clam for 3 months and it has colored up and shown new shell growth since (shiny white layer under the mantle). The top left area of the mantle is what concerns me.
Maybe?
The way the mantle presence at that point looks similar, but I also think I see a barnacle or other creature attached to the shell that may be irritating the clam at that point?
I would give the shell a good look over and possible brushing to eliminate any irritants/pests. If the mantle gets worse, then maybe PMD, but I wouldn't call it PMD at this point.
Some more pictures today, i dont think there is anything on the shell. I checked in the middle of the night with a flashlight for snails or a barnacle. What do you think , fw dip time?
If you can safely pull it out of the water, then I would scrub the shell and inspect it out of the water. Don't worry, it'll be perfectly fine. There are small hydroids that can irritate the mantle and they are almost clear (more opaque) and hard to see. If the mantle recession starts to expand, then performing a freshwater dip may be the fix. My guess is there's something you can't see that irritating the mantle.