Mystery snail (not moving much)

[littlebigfish]

I have 1 yellow mystery snail, and 3 blue mystery snails (and a few other fishies). My problem, or rather a question about one of the blue ones...is that it has been just hanging out so to speak in one spot, it doesn't seem to move. I keep checking it sometimes I think that it might have died, because it looks relaxed, and kinda out of its shell, on its back...I go to move it and it clams right up. I don't know if this is normal behaviour, or can something be wrong with it, and should I separate it from the others?? Someone at Petsmart told me that it could be molting??? Do they actually do that?? If so how long do they normally do that for?? Any information would be greatly appreciated.
Cheers

 

[tmtpowers]

I am by far no expert on snails but I have seen them go dormant for several days at a time. I've even seen them float for a day or so. As long as there is calcium being supplies to your snails via supplements, food, cuttle bones, ect and the ph isn't too acidity (at minimum 7.6 from what most snail breeders have told me) than I would just let him be. check in every now and then to make sure he is a live but odds are he is fine