HCA: Hermit Crab Association

i want to get some shells for my crab but i don't know how to measure him, i tried a ruler but he was walking around too much. the shell he's in came with an identical shell and i measured that and got 1" on the widest part. would that be okay to go by or do i need to measure his claw?? thanks in advance https://imgur.com/Ax19T2P

if he fits well in the shell he’s in and the one you measured is identical i would order at least three the next size up or so
so if it’s an inch then u can get few that r 1 1/8”
u basically measure the opening of the shell and but a few that have openings just a little bit bigger than his current shell

thank u sm 🥺 ur a lifesaver

awh ofc!