Choosing Hermit Crab Shells

Hermit crabs have adapted to using shells washed up on shores as a survival strategy; predators cannot reach the crab when it withdraws into the shell, and the crab is better suited to life on the beach.

It is a common misconception that hermit crabs change shells when they molt- in fact, they have nothing to do with each other. When hermit crabs molt, they can change shells if they want to, but do not need to necessarily.

If you own hermit crabs, shells should be chosen with careful attention towards its size and shape in order to find the best fit for your crab. Imagine wearing clothes that don’t fit; sizes too small or too large are uncomfortable for them, as well.

Additional Sources: 

• How To Choose Hermit Crab Shells By Shape and Size
• Complete Hermit Crab Care
• Care of Hermit Crabs

The first step is to determine the hermit crab’s species. This is not completely necessary, but certain types of crabs prefer some kinds of shells to others. For example, Ecuadorian crabs are known to prefer shells with D-shaped openings over ones with round openings, as they have wider, flatter thoraxes than Caribbean crabs. They are also known to stick with one shell for a long time, even if it is a bit too small, whereas Caribbean crabs tend to change shells more frequently.

 Each hermit crab must be provided with an array of shells so they can switch shells when they need to. When adding shells to the crabitat, remember to look for shells with similar-sized openings and not necessarily similar-sized shells. Hermit crabs can be quite picky about the shells they choose, so be sure to have a variety of them; if you think your crab’s shell is a little big, add some that are a bit smaller. Without a good selection of shells, shell fights are more likely to occur, and this can be fatal to your hermit crabs

Shells are not just accessories; they are imperative to the crab's survival. Without a shell, a hermit crab becomes food for other animals. And since hermit crabs are forced into a painted shell, they're often not the right size. In addition, sand can scrape off the paint of shell (which could be toxic) and contaminate the food, water, even the entire crabitat.

Sometimes, when the crabs are forced into shells too small or that have wet paint, they can get stuck inside their shell and die slowly of starvation.

Although painted shells look pretty in pet shops, hermit crabs are usually forced into these shells through several types of painful and terrifying experiences, such as:

- cracking the crab's shell so he is scared out of it and the only other choices for shells are painted

- attempting to yank the crab out of his shell (only most crabs are ripped in half)

- drilling a hole in his shell, then poking him until he is scared frightened out of it

- shoving a hermit crab in the freezer in order to slow him down, then inserting him into the painted shell

- leaving food on one side of the tank, then blocking the crab from reaching it unless he leaves his shell, and once he does, replacing his shell with a painted one

Painted shells are cruel, dangerous, and the manner in which hermit crabs are forced into them is even worse. Not only are they harmful and potentially-disastrous, painted shells can look just plain ugly and even tacky. Natural shells can be beautiful as well as realisitic, and are a much better selection.

When shell-hunting, please do not buy painted shells and make a good choice for you and your crabs. Your crabs will live happier, healthier lives- and you won't have to spend as much money.

Photos by: Aschaf, tink tracy, blaire_25, and jenny downing