Today I purchased a Maxima Clam (about 3-4") from a local fish store. I have two clams already in my tank both of which are doing well. All my params are in check, I am running 2 Hydra 26's over the tank, and placed the clam on the rock work seeing as they are rock boring clams. I burped the clam before I placed him in my display tank to make sure no pyramid snails were on the foot (which I also did in the fish store). The clam has a little bit of the tissue exposed however it is no where near to being fully open. It is impossible for me to see if the clam is gaping because it is simply too closed up. In the past when I added new clams some gaped for a few hours before retaining a healthy look while they adjusted to the new tank yet this clam is puzzling me. I forgot to mentioned I drip acclimated it for 45 minutes before adding it to my tank. Has anyone experience this before? I have read several forums that have had similar problems but they were addressing pinched mantles as opposed to not being open. I am not new to keeping clams just perplexed. Anyone have any ideas or input?