Care and feeding

Housing

Hermit crabs are not too fussy about where they live, as they already carry their homes around on their backs, but they are quite particular about the temperature and humidity, which are important to their health. They come from tropical countries, where it tends to be warm and humid most of the year. Your best bet is an aquarium of at least 10 gallons, preferably of glass, with a lid that can keep in the humidity. Still, the larger the tank, the better, as this will allow you to put in some furnishings (alas, not those pretty coffee tables and lazy-boy loungers from Ikea!) - one that has enough space for one or two more crabs if you decide to introduce others crabs to its neighbourhood at a later stage.

Ask the pet store attendant to recommend a few extra shells that your hermit can move to when it outgrows its current one, and wash and clean these out well with plain water before placing them in the tank. You could also try boiling the shells for a few minutes to make sure they're really clean - just make sure that the hermit is not in any of them at the time, unless you're trying out mum's recipe for crab soup!

Its bedding, or 'substrate' if you want to be all scientific about it, should be a layer of sand, as hermits naturally like to burrow. Calcium-based sand is great, and is available at good pet stores: crabs tend to eat it to keep their shells hard and healthy. You're likely to find colourful sand of this type, too, just in case Hermie is the artistic, home-proud type.

There are other good reasons to use sand, too. Wet waste makes the sand clump, and it is easy to clean these clumps away, plus the sand can be washed and dried if you have the patience for that sort of thing.

If nothing else, use plain playground sand, but remember to wash and dry it before using it to line the bottom of the tank. Let the sand be just a little bit moist, as this helps the crabs to 'moult' or shed their skin. Other options are fine gravel or river stones, but my advice is use sand because burrowing is easiest in this kind of bedding. Just don't use wood shavings, and your hermit should be fine.

Temperature

Land hermits like a balmy 72-85 degrees Fahrenheit, and if the temperature drops below 72 degrees, they tend to become weak and sluggish, and sometimes even fall sick. Unless you're living in a naturally warm country, you will need to use a heater at least part of the time. The best option is an under-tank heater, like the kind used for reptiles. A thermometer will help you keep an eye on the heat levels, and if you find that the heater isn't doing a good job, it might be because there's too much sand covering it, and if it's heating up too much, the opposite might be true - there might be too little sand covering the heater.

Placing the heater under one part of the tank ensures that the temperature is not the same in all areas, so that the crab can move across to get cosy to the warmer areas when it's cold, and to the cooler bits when it's feeling a little toasty. Just be sure to let the area that's coolest stay at least 72 degrees warm.

Humidity

If the air is too dry in the tank, the hermit might suffocate, because it relies on humidity for breathing. Go for a relative humidity of about 70 percent, and again, you will need a humidity meter to let you know if the conditions are right. Too much humidity could encourage fungus growth. The water dish in the tank keep the tank humid enough, so long as the tank is enclosed by solid sides and a good lid. If the humidity drops too low, place a large chunk of natural sea sponge in the water dish, but make sure the water is free from chlorine.

Light

Hermit crabs are nocturnal, which means they are more active during the night, so it's important that you do not use bright light in the tank during nighttime. If you absolutely must check on Hermie at this time, use a special light that gives a moonlight-like glow, but make sure it is of less than 15 watts' power.

Furnishings

The furnishings in the tank should consist of three things: stuff to climb on, a water bowl, and a food dish. Cholla wood is perfect for climbing, and can be arranged to allow your crab to get a foothold to climb about easily, but you can also use coral, driftwood and some other types of wood. The pet store might also have specially made plastic bits that let your crab climb, bask and hide, which are also easy to clean at the same time. If you're clever, you might also want to try using Lego building blocks to make interesting climbing structures to keep your crabs challenged at all times.

Food and water

Food-wise, land hermit crabs are omnivorous, meaning they eat both plant and animal matter, but that doesn't mean you can chuck in your green peas or broccoli when mum isn't looking. You can use the diets available at the pet store, although not all pet stores keep these. If this is hard to find, you can feed your crab a balanced diet by including a variety of fresh foods in its meals. Remember to clear out uneaten food everyday, though.

Here are the different kinds of food you can feed it; use a combination of a few one day, then a mix of others another day: mango, papaya, coconut (fresh or dried), apples, applesauce, bananas, grapes, pineapple, strawberries, melons, carrots, spinach, watercress, leafy green lettuces (not iceberg or head lettuce), broccoli, grass leaves, unsalted nuts, peanut butter (occasionally), raisins, seaweed (found in some health food and grocery stores), unsalted crackers, unsweetened cereals, plain rice cakes, cooked eggs, meats and seafood (in moderation), freeze-dried shrimp and plankton which you will find in the fish food section at the pet store, and fish food flakes.

Avoid citrus and acidic fruits like oranges and tomatoes (yes, the tomato is actually a fruit), starchy vegetables like potatoes, and dairy products like cheese. Also try and feed them calcium in the form of calcium and vitamin supplements, crushed oyster shells, and even crushed eggshells.

The water bowl your hermit will use should be large enough to let it move about easily in, but not so deep that he or she could drown in it. Use small stones and pebbles as steps to let Hermie climb in and out of the pool. Be sure to use some water dechlorination treatment, which you will find at the pet store.