Grab a ruler or tape measure and measure your hermit crab’s current digs! You'll want to measure the widest part of the shell opening—that’s the key to selecting the right size up. When shopping for new shells, aim for ones that are about 1/8" to 1/4" larger to give your little buddy room to grow.

Hermit crabs love options, so be sure to offer a variety of shell styles and sizes—at least 3 to 5 per crab is ideal. This helps avoid “shell envy” and those occasional crabby squabbles. And don’t forget, hermit crabs can be total divas when it comes to fashion—beauty is in the eye of the shell holder!