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How to Build a Hermit Crab Habitat

A complete habitat and care guide

A close-up of a hermit crab

Pablo Zgraggen / EyeEm / Getty Images

Many people mistakenly think that all hermit crabs live in the ocean, but unlike the habitat of marine hermit crabs, land hermit crab habitat is near the shoreline. This provides them with easy access to water when they need it, such as when they reproduce or need moisture. And this is necessary to consider as you build a habitat for your pet hermit crab.

Hermit crabs don't need an elaborate home, but the appropriate temperature and humidity are vital to their health. Land hermit crabs, the most common type of pet, come from warm, tropical climates and, therefore, need a warm, humid environment to survive. Here’s a guide to setting up an enclosure that will give your hermit crab exactly what they need.

Picking the Tank

Despite their name, hermits are quite social and are best kept in groups. To house your hermit crabs comfortably, keep the following in mind:

  • Hermit crabs will feel at home in either a glass or plastic tank.
  • Choose a 10-gallon aquarium with a lid. A sliding glass one will work well to contain humidity.
  • The small plastic homes with accessories sold as hermit crab kits are too small, though these plastic cages make excellent temporary homes or isolation tanks.

The Substrate

Avoid the use of gravel or wood shavings. For substrate in a hermit crab tank, good options include:

  • Sand: This is the substrate of choice for hermit crabs because they like to burrow down into it. Playground sand, which can be found at home improvement stores, works well and is inexpensive, though aquarium sand is fine as well. You may want to rinse, dry, and bake the sand (at 300 F) to sterilize it, and it can be rewashed and used again. Calcium-based sands are nice and come in a wide array of colors but are expensive.
  • Fiber Bedding: Products made for reptiles, such as the coconut fiber-based bedding called Forest Bedding, can be used in hermit crab tanks, too. The fiber is ground quite fine and is nearly like soil, so it is good for burrowing.
  • Crushed Coral: This is a nice choice, but you may want to provide an area with Forest Bedding or sand, as your hermit crabs may prefer these substrates for molting.

Maintaining Proper Temperature

Hermit crabs are happiest kept at 72 to 80 F (22 to 27 C). If the temperature drops below 72 F regularly, the crabs will likely become weak, stressed, and ill.

  • Heater: Unless you live in a tropical climate, you will need to use a heater at least part of the time to keep the crab tank at optimal temperatures. Under tank heaters (UTHs), lights, or a combination of both can be used to maintain appropriate temperatures. Lights of various types can provide heat for the tank, so some experimentation may be necessary to find the combination of lights and UTH that works best for your tank.
  • Warm and cool sides: The UTH can be placed under one end of the tank to provide a warm side and a cooler side. This will raise the temperature a few degrees above room temperature. For ideal temperature control, it can be combined with a thermostat to maintain a given temperature, or you can put it on a timer to come on and off to maintain temperatures. Make sure that there is a temperature gradient in the tank so the crabs have a choice of temperatures.
  • Adjust the substrate and lighting: Invest in a good thermometer for inside the tank, and monitor the temperature near the substrate. If the heater isn't heating the tank enough, try removing some of the substrate over the heater—the thinner substrate will increase the heat in the tank. If the tank is getting too warm, you can increase the depth of the substrate. Some experimentation may be necessary to get good, stable temperatures.

Lights

In the past, it was thought that hermit crabs were nocturnal and that providing lights could be stressful for the crabs. However, low-wattage and special night light bulbs are a good option. Many crab owners find that their crabs become more active with lighting, and even bask near the lights when the lighting is added to the tank.

  • Daytime and nighttime cycles: Be sure to provide a light-dark cycle, such as 12 hours of light and 12 hours of dark. This means day glow or fluorescent bulbs should only be off at night, though special nighttime bulbs can be used if desired.
  • Lighting hood: The easiest way to add lighting is to use a reptile heating/lighting hood over the tank. Hoods can be found with two ceramic receptacles for incandescent bulbs, so a day glow bulb can be put on one side and a night glow bulb on the other. It is best to start with 15-watt bulbs and go to higher wattages only if necessary, especially with a 10-gallon tank. If necessary, wood slats can be used to raise the hood a bit above the glass if it gets too hot. Some hoods have a third receptacle for a fluorescent bulb, and some owners have reported good results with a Reptisun 2.0 fluorescent. Reptile heat hoods are best used on glass top tanks or screens, though screen tops make humidity regulation difficult, as the lights will be quite warm and could melt the plastic.
  • Don’t overheat the tank: Using a desk lamp or high-wattage reptile bulbs may overheat the tank and be too drying, so these are not recommended.

Humidity

Along with the proper temperature, adequate humidity in the tank is vitally important to hermit crabs. Because crabs "breathe" via gills, the proper exchange of oxygen by the crabs depends on the humidity in the air. If the tank air is too dry, the crabs will essentially suffocate. Excess humidity is not desirable either, as it will cause condensation as well as encourage the growth of bacteria and fungus in the tank.

  • Proper humidity level: Hermit crabs need a relative humidity of around 70–80%. Because this is so important, it is worth investing in a humidity meter, known as a hygrometer, which you can find in the reptile section of the pet store.
  • Water dish and sponge: The water dish you provide in the tank will likely be sufficient for creating the proper humidity, as long as the tank is enclosed with solid sides and top. If you need to increase the humidity level, try a fairly large chunk of a natural sea sponge in a dish of water (remember to always use dechlorinated water). The sponge can hold lots of water and has lots of surfaces for evaporation to boost the humidity. Have a couple of sponges on hand so you can swap and clean them frequently (soak them in very hot dechlorinated water or a sea salt/water mix, then allow them to dry completely, as they are a good medium for bacterial growth).
  • Modify the top of the tank: If a mesh or vented lid is making humidity control difficult, it can be modified by covering most of the top with plastic wrap or clear packing tape.

Cage Furnishings 

There are four necessities for furnishing the cage: stuff to climb on, shells, a water bowl, and a food dish.

  • Climbing: Land hermit crabs love to climb, and this is a good way to provide some exercise. Choya (or cholla) wood is ideal and can be arranged to allow climbing. Pieces of coral, driftwood, and other types of wood can be used—the reptile section of the pet store is a good place to look for a variety, or check online hermit crab retailers. Artificial plants are also a great addition to the crab tank. Periodically change things around or add different items to provide some variety and interest for the crabs. Some enterprising individuals even use Legos to build climbing structures for their crabs.
  • Shells: As hermit crabs grow, they leave behind their shells and take on larger ones that suit them better. But stressful situations could also cause shell evacuation. So, add several clean, empty shells that your crabs will be able to use whenever they wish. You can offer different types of shells of varying sizes to see which ones your hermit crabs prefer, and then offer more of the same types but in larger sizes as they grow. 
  • Water: Hermit crabs should have access to both fresh water and salt water, so you will need two water dishes. They should be big and deep enough to let the crabs get into them if they wish to soak—especially the salt water dish—but easy to get out of and not so deep that drowning is a risk. Strawberry hermit crabs should be given a salt pool deep enough to fully submerge themselves, but for most species, it does not need to be that deep. To create steps or ramps that your crab can use to get out of the water, place coral or smooth river stones in any dishes that are deep. Place natural sea sponges in the water dishes so your crabs can use them to drink water (plus, they help with regulating the humidity in the tank). All water given to the hermit crabs or used in the tank should be dechlorinated (the drops available at pet stores). Salt water should be prepared using a marine aquarium salt like Instant Ocean (a mix for saltwater tanks), not the salt made for freshwater tanks, and never table salt.
  • Food: Food dishes that are sturdy and shallow, as well as easy to keep clean, are best. You can use flat, plastic dishes that look like rocks (check the reptile section at pet stores). Ceramic dishes that are shallow and designed for small animals can also work well. And you can even use seashells to feed your crabs.
Essential Hermit Crab Supplies

The Spruce / Ashley Deleon Nicole

FAQ
  • What paint can I use in a hermit crab habitat?

    The best paint to use around hermit crabs is acrylic paint—just make sure to keep it away from the inside of their shells.

  • What kind of rocks should I put in a hermit crab habitat?

    After using a good layer of sand as substrate, small river pebbles are great for hermit crabs.

  • What can live in the same habitat as a hermit crab?

    Hermit crabs can coexist with other hermit crabs and freshwater crabs. In fact, hermit crabs do not do well as solitary creatures, so keeping them with at least a few other hermit crabs is preferred.

  • Why does my hermit crab habitat smell?

    A number of things can make your hermit crab's home stinky: infrequent cleanings (which leave molted exoskeletons hanging around), waste, and old food. Hermit crabs also release pheromones with an unpleasant aroma when they are stressed, and this can happen when their habitat is unclean, if they are handled too much, or are lonely.

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  1. Land Hermit Crab. Smithsonian’s National Zoo & Conservation Biology Institute.