Help my clams

[cimpow137]

I have 4 Crocea clams that all of the sudden started closing during the day a couple days ago. They stay open at night, but during the day they are shut tight. I can't figure out what is wrong with them. I don't see any parasites and I have inspected each clam carefully. I did recently buy 2 smaller clams and I also changed my MH bulbs, but the closing didn't start until a few weeks after those events.
Please help me. I don't wanna lose my clams.

 

[chilwil84]

whats your parameters and other inhabitants, daytime closing may have to do with a fish picking at it and the clam realizes the fish isnt active at night

 

[cimpow137]

I do have a Kole tang that picks off their shells. I've never seen any bite marks on the actual mantles. I guess that could be the issue. I just didn't think that he could cause all the clams to stay closed. I really hope he leaves them alone. He's my favorite fish and the clams are my favorite invertebrates. :help: Any other ideas about what could be going on?

 

[teen]

did you check for pyramid snails?