Friends!
I'm sure you've heard this before, but you really shouldn't keep only one hermit crab alone as a pet. The name 'hermit' is misapplied to our little friends -- they are quite gregarious and like to be around their own kind. In the wild, they travel in packs of up to 100 crabs, scavenging the beach for food and shells. The reason they travel in packs is simple: Where there are more crabs, there are more shells. Researchers have found by putting one clean, empty shell on the beach, they can initiate a "cascade" of shells changes: One crab changes in to the new shell, another changes into his old shell, and another changes into the other empty shell, and so on. Quite often I find about 20 hermies of my clan all piled on top each other, sleeping. So, please don't consign your friendly hermie to a life of loneliness. As one seasoned crabber once remarked, "Two crabs does not a colony make." Go get him a friend, or better yet, two friends.
Housing
The very first thing your new pets will need is a 'crabitat.' A crabitat is where your hermit crabs will spend most of their time, so choose a home that is clean and roomy. A 10-gallon glass aquarium can be purchased at a reasonable price and makes an ideal 'starter home' for your crabs. If you are unable to purchase an aquarium, there are other options available, such as plastic critter carriers. Keep in mind how many crabs you ultimately plan on housing and how you would like their home to look. It will help you make up your mind when the time comes to decide on the size of your crabitat. Make sure the cage will hold your pets, their food and water dishes, extra shells and climbing toys. You want a cage large enough to hold all these things and still have space for the crabs to roam if they wish. This means that the small plastic box that you got from a mall kiosk or boardwalk store is not an adequate shelter for any hermit crab. One way to give the crabs room to wander is to leave an area at the back or front of the crabitat that is completely clear of obstructions. This way the crab has an "express lane" to run down if s/he needs to get some energy out and doesn't want to climb. While a plastic critter carrier makes a passable temporary home or 'hospital cage,' it is not recommended as a permanent home.
The second most important aspect of the crabitat is the type of substrate you put on the bottom. After all, your crab will in all likelihood be sitting on it every day! There are many different types of substrate available, but not all of them are ideal for land hermit crabs. You want a substrate that is relatively easy to clean, attractive and holds up to hermit crabs' tunneling activities. The best substrates are sand and coconut fiber (also known as Forest Bedding�, Bed-A-Beast�, and Eco-Earth�.
Sand. There are also many different varieties of sand available. The most expensive ones come in small bags and are labeled as special "hermit crab sand." Don't be fooled! When it comes to general crab care, "sand is sand is sand" and it doesn't matter where it comes from, as long as it is clean. You can get a 50 lb. bag of clean play sand from a hardware store for the same amount you'd pay for 2 small bags of "hermit crab sand." (Try to get a bag of play sand which is towards the middle of the pallet, otherwise, it may be wet or contaminated.) A word of caution about play sand. Some crab owners have reported problems with an orange-colored play sand they purchased from Home Depot. The sand had an oily, diesel-like smell to it. If you open the bag of sand and notice any "off" smell, throw it out or take it back to the store. Do not put any strong-smelling sand into your crabitat. One sand that has been of consistent good quality is "high desert sand." You only need to concern yourself with special sand if you have a sick crab that needs calcium. Most sand comes pre-washed and/or sterilized. Sometimes, however, individual bags can develop leaks through which moisture, insects, etc. invade. As a precautionary measure, please take a close look at the substrate before you put it into your crabitat. Pour some into a bowl and sift it through your fingers, hold it to a strong light and watch for insects. Lastly, put your nose to it and take a whiff to check for a musty smell which would indicate moisture contamination.
Coconut fiber (Forest Bedding "FB" or Eco-Earth) is another excellent substrate. The coconut is processed to be very fine, almost like earth, and pressed into a dry, hard brick. To prepare FB, you put the brick in a large bowl or tub and add enough water until the brick absorbs the water and become soft enough for you to break apart with your hands. Then you add the moist FB to your crabitat. There are many benefits to using forest bedding, not the least of which is that it appears to be one of the very best molting mediums out there. Over time, the FB compacts a little bit and becomes stable, which allows the crabs to dig little tunnels all through it. An advantage of the FB over sand is that FB will not collapse heavily upon a newly-molted crab and damage it. I have had many beautiful molts in the FB. The moisture in the FB helps to keep the humidity in the crabitat at a good range, without resorting to sponges and misting. FB prepared as directed above is adequate, but if you want to make it extra special and healthy, you can prepare it using pre-prepared salt water instead of regular water. First you mix up your salt water according to the package direction, and then use the salt water to soak your FB. Hermit crabs love to eat FB and this helps them to get other, needed minerals in their diet. There is one unique drawback to using FB and that is that it attracts fungus gnats. Fungus gnats are teeny black bugs that look like midget mosquitoes. They are attracted to warm, moist areas and will lay eggs and start a colony of their own in your crabitat. Fungus gnat larvae are worm-like with black shiny heads. Since hermit crabs and fungus gnats are both arthropods, you can not use any pesticides in your crabitat or it will kill the crabs! There is however a solution to this problem. Back in October 2003 I found and used
-- biological warfare! You can view all the creepy details on the
FAQ page. Some people who have mixed their FB with saltwater have reported fewer fungus gnats.
Combination substrate is the latest and probably the best idea. It is a combination of coconut fiber and sand. You prepare the coconut fiber as you would normally, and put it in the crabitat. Then you add sand and mix it all together well until it is a nice, diggable consistency. Generally you want your substrate to be the same consistency as the sand you'd use to make a sand castle. Not too dry and not too drippy. There is one universal problem with all good hermit crab substrates. They are messy. Expect to have sand or forest bedding in your kitchen and bathroom at one time or another. Hermit crabs are not the most orderly critters and they do drag sand, FB or what have you into their food and water dishes. Also they bury shells that they aren't interested in. So you'll be cleaning out their dishes and shaking substrate out of shells, no matter what substrate you use! If it's crab-friendly, chances are it's going to be messy.
WATER: DRINKING AND BATHING
The basic rule of thumb for land hermit crabs’ drinking water is this: Do not give the crab any water you would not put in a tropical fish tank.
This means that you’ll need to remove the chlorine and other harmful chemicals from water prior to giving it to your crab. Bottled and filtered water are also acceptable, but usually more expensive. Plus there is no way of guaranteeing that during processing (with bottled water) that the chlorine was adequately removed or (with filtered water) that the filter you’re using wasn’t clogged or contaminated. I’d go with the method below, regardless of the type of water you use.
Removing the Bad Stuff: Chlorine
Chlorine is harmful to land hermit crabs. Repeated exposure to it causes blisters to form on the crabs' gills, resulting in suffocation and death. You can remove this harmful chemical by purchasing from your pet store a general dechlorinator (or tap water conditioner). It’s relatively inexpensive and usually comes in a dropper-style bottle. You do not need to buy a large amount of it (in fact, you shouldn't, because the drops may gradually lose the ability to dechlorinate the water if stored for a long period of time). Try to get a brand with instructions on how to mix only ONE GALLON of dechlorinated water, otherwise you’ll have to do some calculating as to how many drops per quart, etc. Read the instructions on the bottle or packaging. Usually you'll need something like 1 drop per gallon (if the the water, it can be served to the crabs in practically any non-metallic, non-porous container. The two things you need to consider when selecting water dishes for your crabs are: How much water it will hold; and how deep the container is. If you have large crabs, you will need a larger container, obviously. Hermit crabs like to drag themselves (shell and all) into the water dish and just sit there sometimes. They may be replenishing their ‘shell water’ or they may be cleaning out their shells. It’s important you check the water dish daily, and make sure that it is clean and full of water. To clean the water dish, run it under the tap and dry it well with a dishcloth. The best water dishes I have seen are molded plastic or cement reptile-type dishes that look like rock, sea shells, plastic jar lids and individual-serving size small Pyrex casserole dishes. NEVER use anything metal as a water dish. Land hermit crabs are extremely sensitive to metal.
VERY IMPORTANT! Be sure your water dish is not so deep that your smaller crabs will drown in it. If you have large crabs and small crabs together, put pebbles into the large crabs’ dish so a stray small crab will have a way to get out if it stumbles into the large dish. Smaller water dishes and jar lids don’t need a sponge in them, but a sponge is critical if you’re using a large clam shell, which may be very deep toward the middle-back areas. If the water seems deeper than your smallest crabs, don’t take the risk. Put a sponge into the dish.
Wash Yer Dishes!
You may notice when you refill the crabs' water dishes that there is sometimes a slimy residue in the bottom of the water dishes. This ‘scum’ is probably the residue from the (traces of) oil that is used in many commercial crab foods. This oil is used since our hermies need a bit of it in their diet. However, this does NOT mean to add extra oil to their crab food or feed them extra oil -- THAT could kill them! Another culprit could well be the oils from the natural foods (such as the coconut, etc.) you feed your crabs. The scum is probably a residue of this oil, combined with food particles and other items the crabs drag into the dish along with them. It is no cause for alarm. Just scrub out the scum (do NOT use any chemicals, a damp paper towel works perfectly).
To bathe or not to bathe?
There is a lot of debate among hermit crab lovers as to whether bathing land hermit crabs is in fact necessary. When I was growing up it was taken as gospel and was held that way until maybe three years ago at the most. The arguments for and against bathing can both be made to sound very good. Over the years what I have owned hermit crabs, however, I have come to stop bathing them completely. At first this was because I took into my care several species of exotic hermit crabs and I was unsure about their care. As time went by and all my crabs benefited from not being bathed, I decided to abandon the practice. Now my crabs receive a bath only after coming up from a molt, before being introduced to the rest, or in special circumstances.
The general rule for bathing is thus: If you keep the humidity level of the crabitat at the desired level (above 70% relative) then bathing is actually stressful to the crabs. This is not to say that hermit crabs should never be bathed. What they need is to be able to bathe themselves when they feel the need. You should provide them with dishes of