Gaping clam

[christyf5]

I have like zippola experience with this. The mantle is still fully extended, exhalant siphon is doing its thing. The clam is still reactive to changes in light (ie. my hand passing over it) it does sort of close the tissue around the siphon when fish pass by but then opens it again. I have had clams before but I don't remember them showing off their innards at any point like this one. Maybe this one just doesn't have any inhibitions

I just bought the clam on Saturday, I was just wondering if its still acclimating to my tank or if this is a sign of something more serious.

Any advice would be appreciated