SUBSTRATE DEPTH MINIMUM AND MOLT LENGTH DEPEND ON HERMIT CRAB SIZE

The MAIN key to keeping land hermit crabs alive in captivity is to provide substrate that is deep enough and moist enough that your largest crab is able to bury into complete darkness for an extended period of time. 

In nature hermit crabs dig underground, when it’s time to molt, for two reasons.  First, they need the darkness that they get by burying in order for the molting hormone (ecdysone)  to be secreted .  This hormone is triggered by extended darkness and controls the actual shedding of their exoskeleton (ecdysis).  Second, they need the isolation and protection that being buried underground provides them.  A hermit crab that has just shed its exoskeleton is unable to move until it hardens up and regains muscle control.  During this time they are vulnerable to cannibalism by other crabs and predators if they are not protected.  They also need the insulating properties that being buried underground affords them, protection from the elements and dehydration. 

The best substrate for hermit crabs is what they would find in the wild such as beach sand or a sandy / soil mixture. Beach Sand is great to use because it contains bits of seashell and natural sea salts that will be beneficial to your crabs exoskeleton health.  For those of us that don’t have ready access to natural beach sand Clean Masonry Sand, used in the construction industry, is a next best alternative.  This type of sand is beige/tan in color , fairly course in texture and tends to pack and hold moisture very well. Play Box Sand which is available at hardware stores, can be used as well, although it is not my first choice.  Play sand tends to be very light (almost white) in color, more fine than masonry sand and does not hold moisture as well. I have also encountered problems with mold growth due to some stores keeping it outside in the elements, and one particular brand has a distinct odor reminiscent of cat urine that I have noticed and customers have brought to my attention as well.  You can even use Backyard Dirt if no pesticides or fertilizers have been used.

Calcium type sand often sold in pet stores for hermit crabs is not suitable for use in a crabitat. It is very fine and easily sticks to a hermit crabs moist tail. It is also designed to be used dry which does not allow hermit crabs to bury and successfully re-surface after they are done molting. One of the benefits touted for this substrate is that it clumps readily to wet waste material. As stated through out this section, your substrate needs to remain moist, making this sand un-suitable.

Since moisture is critical to enable hermit crabs to bury, you will want to maintain “sand-castle making consistency” of your substrate so that your crabs can dig and pack a cave in which to molt.  Dry sand will cave in on them as they try to bury.  Add purified or even salt water to your substrate mixture as needed to maintain packing consistency. If crabs are buried just mist the surface well until they have resurfaced from molting. When you are certain that no crabs are buried molting, you can remove everything from the cage, then thoroughly moisten and re-mix your substrate to the perfect consistency so that it’s ready for the next molting crab.

Another way to help sand retain moisture is to add coconut fiber to the mixture. At The Crabbage Patch we use and sell a sand mix made from clean natural Florida sand, compressed coconut fiber, ground oyster shell and moistened with salt water. This mixture works well for our crabs and since they are always eating what’s in their surroundings they are getting additional calcium and minerals.
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BOTH FRESHWATER AND SALTWATER ARE NECESSARY

Another very important aspect in keeping pet hermit crabs alive is to provide a bowl of fresh water AND a bowl of ocean salt (not table salt) water in their cage at all times.  Each bowl should be big enough for your largest crab to climb in to.  If smaller crabs within the cage might have a challenge getting in and out of the water dishes, a small natural sea sponge can be placed into each dish to act as a safety bridge to prevent drowning. Hermit crabs use the water to drink, bathe and replenish their shell water (extra water they carry within the back of their shell). By providing both fresh and salt water you are letting the crab decide for themselves what they need.

Chlorine found in tap water is harmful to hermit crabs.  In order to make tap water safe, de-chlorinator drops can be used to remove Chlorine. Another alternative is to use bottled water for your hermit crabs fresh water supply and also use it to mix with aquarium salt such as Instant Ocean or Hermit Crab Soaking Salt to make salt water. Do not use table salt, it contains iodine which can be harmful to crabs. For crab owners that have well water, I still often recommend using bottled water.  Some wells use a salt softening system or have higher levels of minerals. When mixed with the additional minerals in aquarium salt an unknown and possibly unsafe level of salt and minerals could result.
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QUALITY FOOD AND SUPPLEMENTS PROMOTE HEALTH

A good commercial hermit crab food should be available in the cage at all times. This will ensure that your crab has the proper vitamins and minerals that they need to survive. Hermit crab food comes in many consistencies from powder to large, hard pellets. A good rule of thumb is small, soft food for tiny crabs. Some manufactures recommend moistening their food. A food processor can also be used to change the consistency.

Supplement with fresh produce and protein. Hermit crabs like variety in their diet so it is always a good idea to give them additional fresh items in their food dish.
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PROPER TEMPERATURE AND HUMIDITY PROVIDES COMFORT

Hermit crabs are cold blooded animals which means they rely on their environment for body temperature regulation. Ideally you want the temperature of your crabitat at 78deg F and the humidity at 80%. When hermit crabs have the proper temperature and humidity they will remain more active.
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EXTRA SHELLS PREVENT FIGHTS

It is always important to have extra shells in your cage. Because of their soft tail a hermit crab highly values the protection of their shell. They never walk around without a shell unless they are highly stressed. Hermit crabs are always on the search for a better shell. If they do not find an empty on that fits their needs, they attempt to steal a shell from another crab. Having extra, properly sized shells available will help prevent shell robbing.

Shells are sized by their openings, not overall size. Look at the shell your crab is currently in and choose shells that are about the same size and slightly bigger. Hermit crabs grow slowly so a gradual increase in shell size is best. If they are too big the crabs will not try them on. The easiest way to find the right size is to bring your crabs with you when you go shell shopping.
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PLACES FOR HIDING AND CLIMBING PREVENT STRESS

Hermit crabs love to climb and hide. On some of the islands they call them Tree Crabs because they spend much of their time up in the trees, especially during mating season. They also climb instinctually when the barometric pressure drops and rain is approaching.

We feel it is important to minimize stress to your crabs by giving them a place to hide. When given the choice hermit crabs will spend most of the day sleeping in a hut. Climbing into a shelter makes them feel less exposed and vulnerable. Even if you have a large cage with 1 hut, the majority of the crabs will chose the hut. It is natural for them to pack in it on top of each other.
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FRIENDS ARE IMPORTANT

Related to the behavior above, hermit crabs are very social animals. At The Crabbage Patch we will not sell a single crab unless we know they are going home to be with friends. When a hermit crab lives alone they tend to become very inactive and have a shortened life span.

In the wild they reside in large colonies. In captivity they tend to congregate in piles, usually in the corner of the cage.
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