By 
Since your home is your castle, you want your pet’s cage to be as cozy as possible. You’re right if you’ve noticed that the requirements for hermit crabs are lower than for other creatures. Hamsters and guinea pigs, for example, need a much more complex home than your hermit crab needs.
Maintaining a healthy environment that will keep your pet happy is the most important consideration and will make your pet feel ‘home sweet home’.
Think “tropical paradise.” Your task when setting up your hermit crab cage is to make it as humid and tropical as possible.
The tank is the first consideration that you can choose between plastic or glass for the construction of the tank. Crustaceans are known to be escape artists and you will have a challenge on your hands to maintain your “Houdini”. You will save yourself time, worry and ensure their safety if your cage has a closable top.
You will find kits specially designed for hermit crabs. You should avoid these kits as they are plastic, which is not necessarily a bad thing, but they are usually too small to provide the space your crab needs.
The bigger the better – As with the number of crabs you own, you should select the largest tank you can afford. The best size tank to look for is one that is 10 gallons or larger. Not only are you housing Harriet the hermit crab, you need to have room for a water bowl and other items that she can enjoy playing with.
Substrate: the floor covering
Sand is the best option for the floor or cage of your crabs. It is the substrate material they are familiar with in their natural environment and will make them feel like they have never left home. Sand is great for her to dig in as crabs love to dig in sand as that is what they do naturally.
You can use “play sand” that you can easily find at home improvement, hardware, and children’s toy stores. You will need to sterilize the litter before using it. Sterilize the litter by rinsing it and then letting it dry. Then bake in a 300°F oven. Every once in a while you’ll want to re-wash the sand.
Litter is not the only substrate option for your cage. You can use material that is sold for reptile cages. For example, coir-based bedding, which is finely ground and feels and looks like dirt. This will allow your crab to bury itself easily. Another substrate option you can consider is coral. However, you will need to stay away from wood chips and gravel as a substrate material.
acceptable temperature
Wonder creatures are happiest between 72 and 80°F and you will want to keep the tank in this temperature range. If the temperature consistently drops below 72 degrees, your crab may become ill, as the cooler temperatures will cause it to become stressed and weak.
Space heaters are used in homes in colder climates to keep us happy and healthy. Similarly, these crabs can be kept comfortable with a combination of lights and heaters.
acceptable humidity
Temperature is not the only consideration in the happiness and health of these crabs. Humidity is another requirement that you will need to pay close attention to. Crabs breathe through gills even though they are land animals. The humidity in the air allows the transfer of oxygen through the gills of the crabs. You can suffocate if the air is too dry.
Humidity between 70 and 80 percent is required for crabs to breathe properly. Surprisingly, it is not difficult to introduce and maintain moisture in the tank. A container of water that you place in the tank as a water dish will raise the humidity level. Other ways to increase humidity would be to place damp natural sponges in the water dish.
Sponges absorb and retain a large amount of water. The surface area allows more evaporation to occur and increases the amount of moisture in the tank.
Now you can relax and enjoy Harriet the hermit crab knowing that you have met her basic needs. She should be happy and healthy and be with you for years.