Hermit Crab Sand and Substrate Tips
Hermit crab sand and substrate, the material that covers the bottom of the enclosure, is a crucial element of the habitat. For healthy, happy hermit crab pets, it’s important to understand how they live in the wild, and try to provide a similar sand and substrate in your hermit crab tank or habitat.
Substrate in the Wild
In the wild, hermit crabs live at the ocean’s edge along beaches, sandy dunes, in mangroves and forest areas and even along mountainous zones sometimes towering high above crashing waves below. Hermit crabs can be found all across the world, along different oceans and seas and bays. And all are located within tropical or sub-tropical environments.
Because they are cold-blooded, during extreme heat and cold, they must burrow down into the natural substrate in the area where they live, to regulate their body temperature. Here’s more information on hermit crabs are cold-blooded here.
In addition to burrowing and using that sand and substrate for body temperature regulation, they use it to molt. The very elusive and crucial process of molting must happen periodically, and it must happen while a hermit crab is buried. See my blog post to get more information on the molting process what to expect.
Very rarely does a hermit crab survive molting on the surface of substrate.
Burrowing down into substrate is a crucial behavior that’s needed for the very survival of a hermit crab. For more information on the hermit crab molting process, see my blog, here.
Where Your Hermit Crab Pets Come From Matters!
There are lots of different types of sandy substrate found all over the world, just like there are lots of types of hermit crabs. It’s always a good idea to know what type of hermit crab pets you have, and the environment they come from. Providing elements like the type of sand and substrate native to the type of your hermit crab pets will help you to keep them healthier and happier.
Example: Purple Pincher hermit crabs thrive on islands in the Caribbean. These islands don’t all have beautiful white sandy beaches! As a matter of fact, naturally the shorelines are a mix of sand plus a mix of soil and other sediment. These purple pincher hermit crabs also often choose to burrow further inland than other types of hermit crab pets, in the roots of larger trees and in mangrove areas. This substrate is a mix of sand and dirt. (but don’t use dirt in your habitat, use coconut fiber: see my article on Eco Earth for Hermit Crabs here).
These details of the natural behaviors and environment of your type of hermit crabs should help you determine the best parameters and elements for your habitat. See my blog on types of hermit crabs with photos, here.
Do not use gravel or pebbles as Substrate
This “Hermit Crab Kit” comes with pebbles, which should NOT be mistaken for an appropriate substrate for a hermit crab habitat.
There hermit crab kits, and other similar products, are widely sold in gift shops and pet stores selling live hermit crabs.
Not only is the included “substrate” not appropriate, but these “kits” are too small and should only be used as a temporary transport.
Why the Type of Substrate is So Important
Hermit crab enclosures should be kept within “tropical” or “sub-tropical” parameters for temperature and humidity levels, depending on the type of hermit crabs you have and their specific needs. These parameters affect, and are affected by, the type of substrate at the bottom of the habitat.
Substrate should be well-draining, it should never remain “wet” for long (though a quick “rain” every so often is fine, as it mimics nature”. Just make sure that “rain” isn’t heavy, the substrate should never feel very “wet”.
Also, the substrate should never remain completely “dry” for long, because all types of hermit crabs need some moisture in the substrate, necessary to breathe when burrowed and molting.
Example: Purple Pincher Hermit Crabs are found in the Florida Keys and Caribbean Islands, and are used to “sub-tropical” conditions. They do not require the highest humidity levels like most other types of hermit crabs. Also, they don’t need as high of a heat temperature. A good rule of thumb for Purple Pincher habitat parameters is to simply look at the temps and humidity levels of Key Large throughout the year and keep the habitat parameters around those levels.
For Equadorian, Ruggie and other hermit crab types, they need a more careful approach to keeping sustained higher humidity levels and temperatures.
Also, if you have Purple Pinchers (most common type of hermit crabs sold in the U.S.) and want to keep the habitat substrate in line with what they live in, in the wild… check out this AquaNatural Hermit Crab Aragonite sand substrate on Amazon here. This sand substrate is harvested directly from the Caribbean Islands, where Purple Pinchers live. Keep in mind Purple Pinchers tend to live in mangroves and burrow around tree roots, which are a mix of sand and some dirt and silt.
Keeping substrate conditions "breathable"
Weather typically shifts from hot and dry, to rainy and humid frequently where hermit crabs live in the wild. They are used to these changes, and they accommodate in large part by burrowing.
Hermit crabs must be able to dig and burrow easily and safely. And they need some moisture in the air (humidity) while burrowed inches below the surface, to breathe.
Land hermit crabs use a modified gill system that allows them to breathe air (called pseudotracheae). Both this gill system and their bodies require moisture. This is why it’s important to keep humidity in the habitat, mist often, provide water dishes deep enough for hermit crabs to soak their whole bodies and enough moisture in the substrate.
Too dry and they won’t get the moisture from the air that they need for their lungs. Too wet and their breathing can be stifled, in addition to creating a bunch of other potential health issues like breeding mold and mildew. And wet sand can stick to their bodies, getting inside the shell and irritate and cause issues with their soft moist bodies.
IMPORTANT NOTE ON SAND & SUBSTRATE:
Many experienced hermit crab pet owners disagree on the best substrate for hermit crab habitats. Read any number of blogs or reddit posts on best substrates, and you’ll find multiple answers.
This is OKAY! Remember: every hermit crab habitat has a different humidity level, different elements inside and different dimensions and possibly different types of hermit crabs! All of these differing factors means there is no right answer on the exact type of substrate every single hermit crab habitat must use!
Start with what most experienced hermit crab pet owners suggest, and over time adjust your substrate as it serves your unique habitat the best.
Author note: I prefer using Hermit Beach sand substrate at about 80%, with another 20% of coconut fiber mixed in. See below.
Natural sand plus coconut fiber
Most types of hermit crabs found around the world live right at the ocean’s edge, most likely on or near a sandy beach. The sand is relatively fine but will be like a fine crushed coral. Purple Pinchers are the one type of hermit crab that is known to live further back into mangroves further away from the ocean’s edge, and that substrate will have a little more dirt mixed in.
In general, the substrate should be mostly sand: clean, natural beach sand. But because hermit crab habitats need to retain sub-tropical to tropical (depending on the type of hermit crab) high humidity levels, adding coconut fiber usually works well to help retain moisture. In the wild, that moisture and humidity comes from the ocean that’s right there! So it’s important to remember where your hermit crabs live in the wild, and help recreate that environment.
Most experienced hermit crab pet owners agree that a combination of sand plus coconut fiber (coir) works best in most hermit crab habitats. Why? Natural sand is what is found in the natural habitat of hermit crabs, and the coconut fiber (coir) acts to help retain moisture and humidity.
There are many different types of sand, but it’s always best to stick to natural aquarium safe sand when possible. Many hermit crab owners prefer to use non-toxic play sand… it’s an inexpensive alternative and comes in large bags easily purchased from local big box stores.
Author note:
I’ve been creating hermit crab habitats and raising hermit crabs for 30 years, since childhood. I’ve tried all kinds of substrate, products and combinations.
My personal preference these days is to use Fluker’s Hermit Beach sand substrate. It’s a natural calcium carbonate sand, with added coconut fiber and sea salt, plus added probiotic. I like the mixture, I think it works well not only to help keep the habitat healthier and cleaner, but it’s also a really good mix and consistency for retaining some moisture. I add about 20% additonal coconut fiber to parts of the substrate (usually the corners of the habitat). And in some spots I add a little more of the coconut fiber, and in the very front a little less. Why? Hermit crabs like to pick their spots… and when it’s not all the same, they seem to be happier.
Also, I like the look of a more natural, sandy and tropical habitat so I like to keep the very front more sandy. : )
In this Ikea Milsbo Hermit Crab Hack, a tall 27″ wide by 15″ deep x 68″ tall glass enclosure, there are several large hermit crabs that need deeper substrate. Currently the substrate depth is about 9″.
How deep should the substrate be?
Hermit crab substrate should be a minimum of four inches deep. For the smallest hermit crabs, this may seem like a lot. However, young hermit crabs grow fast and molt more often.
A general rule of thumb is to provide at least 3 inches of substrate three times deeper than the height of the largest crab shell.
For medium to larger hermit crabs AND if your enclosure is overcrowded, deeper substrate is needed.
However, with deep substrate comes some challenges.
For instance, do you have a large water bowl that’s placed on top of the substrate? The weight plus water spillage can cause tunnel collapses! Hermit crabs like to tunnel under water bowls, as there is often more moisture there. But this can cause tunnels that hermit crabs are molting in, to potentially collapse. How to avoid tunnel collapse due to heavy water bowls? Use a platform system! Acrylic or wood risers. See my blog post here for ideas on creating more structure under heavy water bowls to avoid tunnel collapses in deep substrate, here.
Last update on 2024-04-27 / Affiliate links / Images from Amazon Product Advertising API