closed crocea

[jaden1]

I have had this crocea(blue) for about three to four years now, and out of the blue this week he hasn't opened up nearly at all. It is about 6-7" and has always been very happy in his home. I also have a 4" gold maxima that appears unnaffected. All parameters are testing normal. Ph 8.3-.4 alk 10-11 ( not very precise test) calcium 400 salinity 1.025-26 temp 79.6 it fluctuates during the day a bit but lights only come on at night in the summer to help with the heat. All my sps are doing fine. I looked at the base he sits on to see if maybe something was attacking his foot. But near as I can tell that isn't the case. He was right beside a sinularia that maybe was bothering him and as such I moved him elsewhere to be all alone. Really stumped on this one. I won't pretend to know much about clams as these two are the only ones I have ever kept. I very rarely loose any corals or fish in my charge and this one is rather special to me. Does anyone have any ideas? Please help. Thanks in advance for your contributions.
Jason

 

[AttackDonut]

Tossing out ideas:

Any tank mates want to nibble on his mantle?

Check, not only the foot, but the base of the shell for small holes bored into it, by parasitic snails.

 

[jaden1]

No I don't see any holes. And I have not noticed anyone nibbling. My cleaner wrasse has taken some good looks though. But that I have noticed as very recent, maybe starting yesterday. So maybe three days into his recession. I find it unlikely he caused it.
Jason

 

[Electrobes]

My crocea sometimes has a fit and stays closed for a couple of days, though not really a week. Eventually it goes back to normal, opening fully. They may be something lodged into the clam, and possibly it is trying to surround it, and while doing it it stays closed.

Check the clam at night to see if any predators approach it, as most tend to be nocturnal.

 

[jaden1]

He seems to open at night. At least last night anyways. Will check again tonight. Driving me crazy not knowing what to do.
Jason