Finatics is a crab-keeper who channels passion for pets into writing.
Hermit crabs dig in substrate for protection and because they are nocturnal. The crabs usually "chill" in the sand during the day and scavenge for food at night when it’s dark. Since they lie in it all day, it is crucial to have plenty of good, healthy substrate in your tank.
There are many different substrate options on the market: sand, forest bedding, crushed coral, gravel, small river pebbles, potting soil, and wood chips are some of the most popular. Keep in mind, however, that not all of these varieties are ideal for your crabs. Some of them prevent hermit crabs from digging, some are too rough, and some cannot hold moisture well.
Below are descriptions of the different substrates and which ones are healthy for pet hermit crabs.
What Substrates Are Available for Land Hermit Crabs?
- Forest Bedding
- Other Substrates
- Harmful Substrates to Avoid
Sand is a fine choice for substrate since it is beautiful and the crabs can easily burrow under it without it collapsing. It’s also inexpensive. You don’t need to buy bags of “hermit crab sand." A 50 lb. bag of play sand for three dollars at the hardware store is just as good as hermit crab sand but is much cheaper.
Before you put any sand (or other substrate) in the crabitat, always check for any insects or cracks in the bag. Sniff it, and if there is an odd smell, do not use it in the tank. Although most sand is washed or sterilized before it is packaged, it’s still a good idea to rinse the sand, let it dry, and bake it in the oven.
The depth of the sand should at least be enough for the crabs to fully immerse themselves in it. It should also be moist, so as you’re setting up the crabitat, add some water to make it damp, but not too watery; a “sandcastle consistency” is what you should be aiming for.
2. Forest Bedding
Sold compounded into a hard brick, forest bedding is an excellent substrate to use in crabitats. Forest bedding is made of coconut fibers that are so finely shredded they almost feel like soil. Over time, it hardens a little so the crabs can dig underneath it. Place the forest bedding in a bowl, add some water to it, and wait for it to soak up enough water to soften and break up easily. To make it healthier, add pre-arranged salt water. The crabs love to eat the substrate, and this gives them dome of the extra minerals they need.
Forest bedding is a nice substrate because it holds in moisture well, keeping the humidity at a good level without having to mist the tank. The only problem with it is it can attract fungus gnats, which are little black bugs may lay eggs in your tank and begin breeding inside it!
3. Other Substrates
Plenty of crab owners instead opt for a combination of sand and forest bedding (makes probably the best substrate for crabs), providing a great consistency for digging. Another acceptable substrate for hermit crabs is crushed coral; the hermit crabs, many owners report, seem to love the crushed coral.
4. Harmful Substrates to Avoid
The substrates mentioned above are suitable for hermit crabs. Gravel (unless very fine gravel), small river pebbles, potting soil, or wood shavings are not acceptable. The rocks are too coarse for the crabs to dig beneath them. They also do not hold enough moisture for the crabitat, and water can pool underneath the rocks. It is okay to use small pebbles and gravel in certain areas of the tank, as long as they are not used as the main substrate.
Potting soil could contain pesticides and other chemicals dangerous to your crabs. You should also avoid using moss, which not only promotes bacterial growth but attracts bugs as well.
A lot of pet stores sell a substrate called Calci-sand, which is very healthy for the hermit crabs to eat. However, it should only be sprinkled in the food dish because when it gets wet, Calci-sand hardens like a brick and blocks hermit crabs from burrowing in it.
NOTE: Never use any substrates like corn, pine, or cedar shavings because they dry hermit crabs out and have even resulted in death.
Choosing the Right One
With so many options, it can be hard choosing the right substrate, especially if you don’t know much about them. As hermit crabs sit in the substrate all day, it’s critical that it's healthy for them. With the proper care, your hermit crabs are off to long, healthy lives.
This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.
Laura on April 24, 2020:
My family recently got a hermit crab. We got it from a neighbor who had rocks in his tank. We found out rocks were not good. Then we were trying to figure out if we should use dirt or sand. This website told us and it was a big help.
ella on July 09, 2018:
I'm about to get hermit crabs and this has helped me out so much!
DD on September 13, 2017:
Thanks I love the website I have been on it for ever it is so help ful BEST WEBSITE EVER
Stacy on July 02, 2017:
Do not reuse the substrate from the snake tank. Who knows what kinds of bacteria the snake might have had. Thoroughly clean the tank and buy fresh bedding.
Pjones on June 29, 2017:
i bought a used tank it use to house a snake he left the bedding in it i believe it is like coconut hair is it alright to use it or should i start fresh
Hi on March 29, 2017:
Can you use clay for hermit crab substrate?
I'm planning a big co-pets system.