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7 Best Substrates For Hermit Crabs

When you decide on getting a hermit crab, you want to set up a proper “crabitat.” One of the most important decisions you can make in setting up the environment they live in will be the substrate.

Your hermit crab will spend plenty of time crawling on, and burrowing in the substrate so you want to make sure it’s as close to its home environment as possible. These little crabs can live for decades, but not if it has a poor substrate.

When you go to the pet store or search online you are met with an avalanche of substrate types. You may come across different types of sand, gravel, shredded coconut fibers, soil, or a mixture of any of these.

The many choices can make your head spin so we have compiled a list to help you sort it all out. Come on in and let’s find out what type of substrate you need for your hermit crab.

Do Hermit Crabs Need Substrate?

Depending on where you purchased your hermit crab, you may have noticed the habitat it was originally set up in didn’t have any substrate at all. It could have only been a sparse layer instead.

If that was good enough for the hermit crab before you bought it, why should you have to worry about providing it? Besides, some brands can be incredibly expensive.

For a happy, healthy, and long-lived pet, you do need a quality substrate. Also, your substrate needs to be pretty thick depending on how big your hermit crab is, or how big it will grow.

Hermit Crabs Come From Tropical Climates

Hermit Crab walking along a tree in the tropics
Hermit Crab walking along a tree in the tropics. – Source

To best suit your new pet you need to try and emulate their natural surroundings. Hermit crabs come from tropical climates such as the Caribbean, and warm, humid rainforests.

Often they are found scurrying around on warm, sandy beaches, among mangrove trees, or in forested areas that have plenty of rich soil that hermit crabs can easily burrow into.

Aside from hiding in their shells, hermit crabs use the ground to escape predators, feel safe, and molt. Molting is the process of shedding their exoskeleton.

When crustaceans grow, their hard shells don’t grow with them. Over time the shell gets to restricting and needs to be shed. It’s like us wearing clothes that are too tight. We can’t wait to get home and shed these tight clothes and get into something less restricting.

When hermit crabs need to molt, they are extremely vulnerable to predation. They have to move very carefully to extract themselves from the old shell, and when they are out, their new shell is very soft.

It needs time to strengthen and offer protection once again. After the hermit crab successfully sheds the old casing, they need time in the dark and peace to let the new shell harden.

They complete molting while underground. In the crabitat, they will burrow in the soil when the time comes. They need a soft, humid substrate that won’t collapse while they are in this vulnerable state.

How Much Substrate Will You Need?

Hermit crab on a white rock in lots of sand
Hermit crab on a white rock in lots of sand. – Source

Chances are you purchased a small hermit crab that’s probably around an inch long or maybe a little smaller. Most commercially available hermit crabs are smaller varieties. Though there are species that can reach 6 inches long or bigger.

The giant Coconut crab is a species of hermit crab that can grow to lengths over 3 feet! But they aren’t made to be pets so no worries there.

Your substrate should be 3 to 5 times as deep as the hermit crab is long. For instance, if you have a 1-inch hermit crab, you need a minimum depth of 3 inches of substrate, though 4 or 5 inches is even better.

A 3-inch hermit crab needs at least 9 inches and up to 15 inches of substrate depth.

How Do You Clean Hermit Crab Substrate?

Hermit Crab looking up from its pebbled tank
Hermit Crab looking up from its pebbled tank. – Source

Cleaning your hermit crab’s substrate needs to be a regular chore in order to keep your little Crabby happy and healthy for years to come. Regular cleaning will help to prevent mold, fungus, and bacteria from setting in and making your pet sick.

Spot cleaning should be done daily. Remove any waste and uneaten food every day. You can use a fine mesh or screen scooper to remove clumped waste and leftover food before it starts to rot.

Depending on how many hermit crabs you have, and how messy they are you should do a deep clean every few months, to once every 6 months.

You can either completely replace all the substrate and wipe down the tank, or you can treat the substrate and reuse it. Make sure none of your little hermits are molting before you start removing the substrate.

How To Clean And Reuse Substrate

Once you have removed the hermit crabs and everything else from the enclosure, take the substrate and put a thin layer on a baking sheet, and put it in the oven. Bake the substrate at 250 degrees F for about 30 minutes to kill any bacteria, mold, or fungus.

Be sure to let it completely cool before returning it to your enclosure. You can do this 2 or 3 times before it needs to be replaced. Either compost or recycle the old substrate if you can instead of throwing it in the trash.

Now, with all that out of the way, let’s find out what substrate you can use for your little hermit.

Best Substrates For Hermit Crabs

1. Fluker’s All Natural Premium Sand Substrate Mixture for Hermit Crabs

First up is a wonderful mix of silica sand, coconut fiber, salt, and calcium which is pretty close to a perfect mix of substrate for your hermit crabs. Fluker’s works with hermit crab specialists to bring you the best products for healthy pets.

Not only is coconut fiber naturally antibacterial, but Fluker’s adds a probiotic to this mixture to help it last longer and stay bacteria-free for as long as possible.

The added salt is a benefit to your hermit crab as it closely mimics its natural habitat. Salt is also a natural antimicrobial that will help to keep the substrate clean.

With a mix of sand and coconut fiber, this substrate—when moistened—with retain its shape and hold up when your hermit crab needs to molt.

Whenever you moisten your substrate, be sure to use dechlorinated water. Chlorine and most tap water can be fatal to your hermit crab. Be sure to use water treatment, or use distilled water whenever you need water of any kind for hermit crabs.

One negative about this substrate is it can become rather expensive. If you have larger hermit crabs or a large enclosure, you’ll need several bags. Also, it can be pretty heavy so you’ll need to make sure your aquarium can withstand the weight.

2. Zoo Med Eco Earth Loose Coconut Fiber Substrate

This is a great substrate for your hermit crab because it has ground coconut fibers which are naturally antibacterial.

Coconut fibers also help to hold moisture to allow extra humidity inside your crabitat. It also retains its shape when your hermit crab starts to burrow. It’s easy to find, and it’s environmentally friendly. 

When you’re done with this substrate and ready to replace it, the coconut fibers readily compost so you don’t have to throw it in the trash. 

One of the downsides to this substrate is the color makes it difficult to find hermit crab waste sometimes. You’ll have to search to find and remove any poop when doing your daily spot cleanings.

Another negative is that coconut fibers since they retain moisture so well, may attract fungus gnats. These are tiny, black flying bugs that feed on fungus and spores. They lay their eggs in damp soil and will multiply quickly.

If this happens you’ll have to sterilize or replace your substrate.

This substrate is much lighter than sand and sand mixtures so you won’t have to worry about how much weight is in your aquarium or on your stand. It’s also a more budget-friendly option.

3. ReptiCasa Loose Coconut Substrate Husk Fibers

Slightly more coarse than the previous entry but still a great choice. Like other coconut fibers, this is antibacterial and helps absorb odors so your house doesn’t smell like a zoo.

It’s also great at keeping your tank humid and retaining its shape so your hermit crabs can burrow without any worry of burrow collapse.

This is another lightweight option if you are worried about how much weight your enclosure can carry. It’s slightly more expensive than the Zoo Med Loose Substrate.

4. Zoo Med Hermit Soil Coconut Fiber Brick

If space is an issue, you can get these bricks. These are just compressed coconut fiber bricks. They need to be soaked in water to expand them to their uncompressed size. Each brick makes 7 to 8 liters of substrate.

With their compact shape, you can store them easier than big bulky bags.

These have the same benefits and drawbacks as the other coconut fiber options in our list, only they are more compact. This option comes in a convenient 3-pack, so you will have up to 24 liters on hand.

One downside to this substrate is it can be dusty when you’re working on rehydrating it. You might want to wear a dust mask when using it, especially if you have a sensitive respiratory system.

5. Josh’s Frogs Hermit Crab BioBedding Bioactive Substrate

Josh’s Frogs is an up-and-coming name in the pet industry. Especially frogs, reptiles, and now hermit crabs. I personally like this company and have dealt with them frequently. Their products are very high quality.

This substrate is a coconut fiber and sand mixture. It contains no salt that can damage live plants. In fact, it’s specifically produced to grow live plants and have a bioactive enclosure.

For those owners who want to have a living ecosystem and make the hermit crab’s enclosure as close to nature as possible, this is the best option. This substrate has added minerals and nutrients for plants, beneficial insects, and beneficial bacteria that help to clean and keep bad bacteria in check.

Having a bioactive enclosure isn’t for everyone. It requires more work and monitoring to make sure everything is working together, but it’s the best environment for your hermit crab when all the parts are working correctly.

This substrate is more expensive, but it has more in it. Bioactive substrates don’t have to be replaced as often as other substrates as long as it stays healthy.

6. Super Natural Moonlight Sand for Aquarium

So far we have only offered substrate options for land-dwelling hermit crabs, but what if you have aquatic hermit crabs? What kind of substrate do you need for underwater hermit crabs?

Marine hermit crabs need a sandy substrate as well. Gravel isn’t recommended for aquatic hermit crabs as sometimes the pebbles can contain sharp edges that could cut the exoskeleton.

Marine hermits don’t burrow in the sand so you don’t need several inches, only an inch or two for them to walk along and clean up.

Super Natural Moonlight Sand contains no artificial colors or dyes that could be toxic for your hermit crabs. It is a naturally white silica sand that will work great for your saltwater aquarium and a hermit crab.

7. Nature’s Ocean Bio-Activ Live Aragonite Reef Substrate

Lastly, but not because it’s the worst one on the list, is a bioactive aragonite sand. This sand is all-natural, just like the sand you’d find on the coast.

This substrate goes beyond simple sand though, it contains plenty of beneficial bacteria to help maintain a neutral pH balance and removes ammonia and nitrates.

This sand holds a higher price tag, but it has plenty of benefits to back up the larger price.

Are There Any Other Substrate Options?

Some hermit crab owners prefer to only use sand as a substrate for their terrestrial hermit crabs. Plain sand is a good option for hermit crabs as long as it stays moist.

You want the sand to clump together and not fall apart when you squeeze it in your hand. If you’ve ever built sandcastles or sand sculptures when you visited the beach, then that is the consistency you want to strive for.

Will Any Sand Do?

Sand can be an inexpensive option, especially if you have to load up several inches of substrate in your tank. It will be very heavy though, so make sure your stand and enclosure are rated for the weight.

At most home improvement stores you can find many types of sand. From play sand, leveling sand, all-purpose, and more.

The best and safest sand among them all is all-purpose sand. This sand is sifted, cleaned, and doesn’t contain any harmful chemicals. It’s also fine enough to be safe for your hermit crab and doesn’t contain larger pebbles or rocks.

Kids playing sand would be a second option, but you have to be careful with this kind. Sometimes manufacturers add antibacterial chemicals to make it “safer” for kids, but these additives could be dangerous for your hermit crab.

Play sand is also finer, and may be too fine for hermit crabs.

What About Gravel?

Gravel shouldn’t be used as a substrate for hermit crabs. It won’t hold moisture, and the crabs won’t be able to burrow as gravel will not retain any shape. Also, gravel can be too sharp and may cut or harm your hermit crab.

Can I Use Soil For Substrate? 

You have to be careful when using soil substrate. Pesticides, fertilizers, or other chemical compounds are often found in soil and potting mixes, all of which can be toxic to hermit crabs.

If you know for sure a potting mix does not have any fertilizers, antibacterial sprays, or other chemicals, you can use soil, but I’d recommend mixing equal parts with sand for a better, lighter substrate that will still hold its shape.

Calcium Sand Is Sold In Pet Stores, It Must Be Good Right?

There’s a big debate about calcium sand (sometimes called calci-sand, or calcium carbonate sand). It’s sold in nearly every pet store and sold online, and many pet owners swear by it.

When looking at reviews, there are plenty of people who say they’ve used it for years without any problem. Then there are others who think calcium sand is the worst thing ever made and have horror stories about pets who were harmed by it.

I personally don’t care for it and will not use it. I have tried it out, and for a long time I had no problem, but when I did have a problem, it caused a heavy vet bill.

The biggest problem with calcium carbonate sand is it can harden and stick together when it gets wet. It can stick to your hermit crab-like glue, or even become too hard for him/her to burrow into.

Using calcium sand for your pets could be like using power tools without safety glasses. You may never have the need for them, and maybe you’ll never get anything in your eyes, but there’s always a chance a piece of debris will fly up and hurt you.

Another way to look at it, there are many more, better options out there that don’t have the same problems. Is any substrate perfect?

No, but these other substrates aren’t the center of a big debate either. It’s up to you.

Watch Out For Colored Substrates

Now there are as many colored sands as there are crayon colors. You can find blue, green, black, white, orange, pink, and more. They will all say their dyes are safe and won’t rub off or turn your hermit crab colors, but how safe are they?

We already know that hermit crabs are very sensitive to chemicals and artificial colorings. If you want your crab to live a long time, I’d stay away from the dyed sand and substrates.

Yes, they can be colorful and add visual appeal to your tank, but what if it’s harming your hermit crab? They can’t tell you the green sand is making them sick. 

If you want to add color in your tank, use plants or put a background on the tank for more color. Leave the colored sand alone unless you’re making sand sculptures.

Here’s An Option For The DIY’ers

In today’s world, we all need to figure out ways to really stretch a dollar. If you have the time and want to make your own substrate you can. A great substrate you can make yourself is a mixture of coconut fibers such as Zoo Med Eco Earth and all-purpose sand.

Mix up 5 parts all-purpose sand, to 1 part Eco Earth and you have a substrate that will hold moisture well, allows for burrowing, is naturally antibacterial, and is inexpensive.

In most states, you can get a 40 to 50-pound bag of sand for less than $10. The big expense would be the coconut fiber, but you only use a small fraction, so a small bag should last for a long time.

Common Questions

Can hermit crabs live without sand?

Hermit crabs need some kind of soft, shape-holding substrate. If not sand, then coconut fiber or something similar is essential. Hermit crabs molt as they grow and need a dark, quiet place to burrow in order to molt. If they don’t have this place they will voluntarily halt the molting process until it dies.

How long can hermit crabs stay under the sand?

Larger hermit crabs will stay hidden away longer than small ones. Average-sized hermit crabs can take between 4 to 8 weeks to complete the molting process. During this time they will remain hidden in their burrow.

Don’t bother your hermit crab during this time unless you smell something rotten in the tank. If there is no rotten food, then the crab may have perished in the burrow.


Hermit crabs need a deep substrate that will hold their shape when they burrow. The substrate needs to be 3 to 5 times as deep as the hermit crab is big so they can completely cover themselves.

You can purchase coconut fiber or a mixture of sand and coconut, or you can mix your own batch of the substrate if you have the time and want to save some money. Just be sure to keep it damp with non-chlorinated water and make sure no mold or fungi grow on the substrate.

We’re glad you stopped by, so why don’t you leave us a message below? Just say hi, or tell us what you think. Is there something we didn’t cover that you’d like to know about? Let us know.

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