Hermit Crab Shells: Correct Fit and Best Types
Hermit crab shells come in all shapes and sizes. You can find them on beaches, in gift shops, in your local pet store and on Etsy and Amazon. It’s important to provide extra shells for your hermit crab pets at all times. But there are certain types of shells that are best for hermit crabs.
What you need to know about hermit crabs (and shells):
- they need multiple extra shells to choose and grow into
- there is a correct fit for hermit crab shells
- they have shell preferences, and can be picky
- not all shells are suitable for hermit crabs
- painted shells are pretty, but be careful
- there are specific types of shells that work best
Hermit Crab Anatomy Hidden Inside the Shell
Here’s a diagram of a full hermit crab body. The hard shell protects its soft, moist abdomen that hides inside. It’s important to provide shells that are the right fit and shape for your type of hermit crab pets. If you aren’t sure which type of hermit crabs you have, here’s my post on Hermit Crab Types of Pets with Photos.
Provide at least 3 extra shells per hermit crab
It’s important to provide AT LEAST 3 extra shells per hermit crab. These extra shells should be similar in size, with 2 slightly larger.
If you aren’t sure which types of shells your hermit crabs like best, provide different types.
Tip: if you have Caribbean (Purple Pincher) hermit crabs, the older/larger they get, the more they love turbo shells!
Tip: for extra hermit crab happiness, rotate the extra shells in and out of the habitat every couple of weeks. Why? Hermit crabs actually GET HAPPY when you add new things to their habitat! They love to inspect and study new shells. They’ll turn them over, try them on, and decide if they like them or not!
What's the Correct Fit for Shells?
There is a correct fit for hermit crab shells. However, in the wild… they will often settle for shells that aren’t ideal. Oddly, it seems like hermit crabs don’t always know when a shell is too small or too large (or isn’t a shell at all!).
But it’s a good idea to know what a correct fit looks like, so you can try to provide the right size shells (plus a couple of slightly larger to grow into).
The hermit crab should fit just inside the opening easily and securely. When folded inside, their large pincher and legs will fit into a shield-like protection for their soft abdomen inside the shell. This provides optimal security from other hermit crabs that might also like this shell and want it for themselves!
Different species of hermit crabs have different body shapes. Caribbean (Purple Pincher) hermit crabs fit best in shells with a more circular opening and narrow spiral.
Not all shells are suitable for hermit crabs
Sometimes hermit crabs will choose a shell that looks way too small for them. Other times you’ll see them wearing a shell that’s way too big! Most hermit crabs seem to prefer shells that have a circular opening like turbo shells, but others sometimes prefer a more oval opening, like conchs or whelks.
Consider the anatomy of a hermit crab, and notice their bottom (abdomen/tail) that needs to fit into and securely hold inside the shell.
Will your hermit crab pets like the shells you provide for them?
In the wild, sometimes shells are very limited and they fight over them. In other places, there are tons of shells to choose from and hermit crabs like to change shells often.
It’s smart to provide more shell choices so you can avoid any fighting and injuries, and also give them the ability to choose the best fitting shell for their abdomen/tail section.
Burrowing, molting then growing is a big part of a hermit crab lifecycle. Every time they go through the molting process, they emerge bigger and happier.
Don’t stunt their growth OR their happiness!
Provide bigger shells for them to grow into. Generally, hermit crabs grow a little (not a lot) with each molt. Provide shells that are just a little big bigger than the one they are currently in (but not too big of a difference).
Try to provide a “slightly” larger shell, a little larger shell and a different new shell. Let them choose. Sometimes hermit crabs will choose a way bigger shell than looks normal, and will eventually change back to something smaller. But changing shells is a big part of their life cycle.
Painted shells are pretty, but are they good for your hermit crab?
Painted shells became popular years ago as a way to bring more money into the hermit crab pets industry. These “cute” shells attracted more people to want hermit crab pets. And more hermit crab pet owners went out to buy more shells… painted, customized, with their favorite football team, etc!
A few things to consider:
– Some hermit crabs don’t like painted shells, and when given the choice they don’t pick the painted ones. Other crabs don’t seem to mind at all. Best rule of thumb, give your hermit crabs options that include natural shells!
– Painted shells aren’t always a healthy choice. If you aren’t sure about the paint used or if your hermit crabs will like it… stay natural.
– Purchase painted shells from a reputable seller only. And NEVER buy a shell where there is ANY paint or modification done to the inside of the shell, ever.
This is baby Fred. He was rescued from an overcrowded touristy gift shop situation.
He came in a tiny little purple painted turbo shell. It took him a couple of weeks before he decided he wanted to be in natural green turbo shell.
Natural is better.
Types of Shells that Hermit Crabs Usually Like Most
Turbo Shells
Turbo shells are generally the first choice of most hermit crabs. Purple pinchers (Caribbean hermit crabs) are the most common hermit crab pets in the U.S., and their preference is usually for shells with a circular opening, and a shell that is medium weight like the turbos. Click for more on turbo shells
Florida Whelks
Florida lightning whelks are fairly easy to find along shelly beaches (ex: Sanibel, Cayo Costa), from tiny to large, and in whole (not-broken) condition… perfect for your hermit crab pets.
Florida Purple Pincher (Caribbean) Hermit Crabs found in the wild, most especially very small hermit crabs… are often found inside these shells if on a beach or in mangroves at the ocean’s edge.
Whelks are gastropods that live in sandy shallow waters just off the coast, so their shells often wash up on beaches in good condition.
Whelks look similar to conchs and are often mistaken for them. They have a left-hand spiral and are usually a light to medium brown or pinkish color. Their opening is large, and a hermit crab body fits into the inside of the shell nicely.
Conch Shells
Conchs look very similar to whelks, but they are a different family of marine life and shell. Sizes range from very small to jumbo, and these shells have a medium weight which is preferred by most hermit crabs.
There are lots of types of shells in the conch family, many are not suitable for hermit crabs. The Strombus and Canarium shells are pretty but hermit crabs have a tough time using them.
Find conch shells with a wider oval opening where they can more easily secure their abdomen/tail section into. In the wild, it’s very common to find hermit crabs inside conch shells.
Frog (Bursa) Shells
Frog shells (part of the Bursa family) have nothing to do with frogs. There can be found in the Caribbean as well as Pacific (and they do wash up on beaches to be found). They are usually small to medium and have an oval opening. Small hermit crabs usually like these shells because they are medium weight and fairly short and easily to maneuver when climbing and burrowing.
Whales Eye Shells
Whales Eye shells come from ocean snails (gastropods). They have a large opening, fairly thin and are lightweight. They can typically be found between 1″ and 3″ (openings) and make good extra shells for hermit crabs.
HOWEVER… many hermit crabs, when given options, will choose a shell with a smaller opening and slightly heavier for better security. For larger crabs, Whales Eye shells can be a good option for extra shells.
(NOT a good hermit crab shell)
Murex
Murex shells are among the most common shells for collectors and hermit crab pets parents. There are tons of different types.
For hermit crabs, there are a few murex varieties that hermit crabs seem to like a lot, but most murex shells won’t be the best choice for your hermit crab pets.
Make sure to choose a Murex shell with a bigger circular opening!
Trochus (Troca) Shells, Easy to Find but NOT a good choice
Troca shells are common to find along many beaches in Florida. In the ocean they are snails that live in and around reefs and shallow warm waters.
They range in size from tiny to several inches. The colors range from white to green to reddish-pink, and more.
These shells, once washed up onto shore, are often inhabited by hermit crabs. If you find a troca (trochus) shell, make sure to look carefully inside before taking it home!
Some trochus have larger more circular openings which is preferred by hermit crabs.
Most often they’ll be polished and beautiful when found in a gift shop for purchase. However, in the wild they are usually white and unattractive and most often very small.
Storing Your Extra Hermit Crab Shells
Hermit crab pets and their crabitats can be an addicting hobby. Even if you just got your first hermit crab pet… it’s quite possible you’ll still have hermit crabs in 10 years or more.
Keep all your hermit crab shells, you never know when you’ll need them again! If you don’t have the space to store lots of hermit crab shells when they aren’t in use, put them in a basket or glass bowl as home decor!
Last update on 2024-04-27 / Affiliate links / Images from Amazon Product Advertising API