Try PMing a moderator (names are blue on the main forum page near bottom where it shows everyone that is online) and asking them to move this to the Invertibrates section. They will be able to help you better there.
Live ones should change position in the aquarium daily, you should also be able to see tiny movements between the two halves of the shell as they filter their food.
Thanks guys! He did see one open slightly but when he turned on the light, it shut again so I didn't see. It also appears that at least one has changed position, only slightly though.