Chewin’ the Choya » Weird shell choice

My new hermit crab, Churley (Charlie + Hurley, for fans of the TV show “Lost”) has finally chosen a new shell, after much deliberation. It is from the set of shells I got from CVS, which originated in the Philippines. From my research and given the origin of the shells, I believe he has chosen an endive Murex shell, Hexaplex chicoreum. It seems overly large and spiky for him, but his previously vacated shell has been taken by one of the other crabs, Bernard.

I am not sure what will happen to him now. He doesn’t seem interested in committing to any of the turbo shells I’ve presented to him, nor the larger Cittarium pica (magpie pica) shell. There’s plenty of other types of shells, but I’ve since learned that they’re the wrong type and most hermit crabs won’t like them. There’s at least 3-4 turbo shells, but the rest will probably be a bust. I do have what I think are 2 moon snail shells, at least 3 tulip snail or whelk/conch type shells, and some Angaria delphinus (delphinulas, which I read were mostly hated by hermit crabs).

Please see the pictures below of the new shell. The poor crab seems to be having trouble moving around properly. Has this happened to anyone else? I wonder why he won’t just use one of the larger green turbo shells.