Hermit Crabs are super easy to care for pets, right?
Wrong! But I'm sure that you were told otherwise. You were probably told you can keep them in a tiny critter keeper with a wet sponge for water and feed them Hermit Crab pellets from the store. The truth is that that is the equivalent of keeping a cat in a tiny plastic box with very little water and innutritious food; the cat is alive but it is not happy or healthy. Hermit Crabs are exotic pets that require a lot of care to be properly provided for.
The first step to owning Hermit Crabs is setting up their new home with you. You should start by getting the correct sized aquarium for them to live in. Hermit Crabs can reach up to softball size (sometimes larger) so they need quite a bit of space to climb, dig, and explore. They are also social creatures and require at least one other tank mate of the same species. The recommended beginning tank size is 29 gallons long and for each additional hermit crab you would add 10 gallons to the tank size. So if you would want to keep 5 hermit crabs you would need a 50-gallon tank.
Now you're going to need substrate for your tank, 6" of a 5:1 ratio of playsand and Eco Earth, mixed well. It should be wet but not too wet (you should be able to make a sand castle out of it). What you do not want to use is gravel, calcium sand, or almost anything else that says "hermit crab safe" on it at a pet store. Hermit Crabs go through a process called molting in which they shed their hard exoskeleton and regrow a newer, bigger one. During this process, they can regrow legs or claws but it is very stressful to them because they are at their weakest state. To limit their stress they bury themselves, this will protect them from predators and let them peacefully finish their molt. Molting can take anywhere between a month to 10 months, it all depends on the crab's needs. It's also very important to know that you should never dig a crab up. If the crab is molting you will most likely kill it and if it is just digging you will stress it out very badly.
Here comes the fun part... Decorating! Here's a short list of things to add to your tank:
Hiding spots, like caves or a coconut with a hole in it.
Natural (not painted) shells of the correct size for your hermit crab. Paint is toxic to them (yes even non-toxic paint), glass shells are heavy and don't protect them. Only natural shells with round openings are suitable for them. You should put 5+ shells per crab in the tank. To size them you should measure the length of the hermit crab's big claw (length/width down the middle) and get shells with openings the same size as the large claw. The crabs use their big claw like a door so that they can hide in their shell.
Cholla wood for climbing and other things like netting for them to climb on, again no paint!
Let's talk about food and water now. Hermit Crabs are natural scavengers so they will eat just about anything but that doesn't mean you should give them just anything. No salt, fruit with pesticides, meat with seasonings on them, butter, onions, most Hermit Crab food at pet stores, or garlic. There is much more they can't eat but those are common things you should stay away from. Things the can eat are vegetables, fruits, meat (moose, beef, chicken, mice, etc.), nuts, berries, seeds, raw honey, and others. As for water Hermit Crabs need salt and fresh water so you should keep two dishes, deep enough for them to completely submerge in. The salt and fresh water should both be treated with Prime, a fresh and saltwater conditioner that removes chlorine, chloramine, and detoxifies ammonia. One of the dishes should be also treated with Instant Ocean aquarium salt.
Hermit Crabs require heat to survive so you will need to heat the aquarium using Bean Farm Ultratherm Under Tank Heaters or Reptile Basics Ultratherm Under Tank Heaters. When using them make sure to play the heater on the side of the tank and not the bottom because we are heating the air not the substrate.These work best if you insulate your tank by wrapping it in duct insulation that is used for AC units. The tank will also need humidity because Hermit Crabs have a type of gill that use the water in the air to breathe. You will need a spray bottle to spray the tank when the humidity gets too low. It should be kept at a constant 80% (higher is fine). To monitor the heat and humidity you will need a digital humidity and temperature gauge.
The basics of Hermit Crab care is all this article really covers. Good places to look for more help are Facebook groups such as Hermit Crab Owners; I learned everything from the people in that particular group. There will be times when you will have emergencies and will need help, you should go to Hermit Crab Owners because they know just about everything that comes to Hermit Crabs. I encourage you all to spread the words about these creatures and how they are not easy-to-care-for pets and get them the proper care they deserve.