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Hermit Crab Care Basics

Alex loves animals and is an experienced licensed veterinary technician with a BS in Biology and an AS in Veterinary Technology.

This is a species of marine hermit crab in a glass shell. This shows what hermit crabs look like under their shells.

This is a species of marine hermit crab in a glass shell. This shows what hermit crabs look like under their shells.

Hermit Crab Care 101

Typically, most people who acquire hermit crabs as pets are tourists at the beach. Many shops at the beach have attractive signs that promise a free hermit crab if you buy the crab care kit. The problem is that these people working in the shops don't know much about hermit crabs and so-called "crab care kits" are tiny cages with a sponge and a small container of food.

The tourists leave expecting to have everything they need for their new pet. Sadly, this is not the case. These poor critters often do not live as long as they should, and their unsuspecting owners have no idea that their crab should live more than a few months.

It is not complex to care for a hermit crab, nor will they require much of your time. Once you know what you need to take care of your hermit crab, they make fantastic pets.

Hermit Crab Husbandry Basics

Marine vs. Terrestrial Hermit Crabs

There are many different kinds of hermit crabs. Some live on land (terrestrial), and some live in the oceans (marine). It is important to note that you cannot put a terrestrial hermit crab in a saltwater tank and expect it to live. Of course, the reverse is also true.

How Big Do They Get?

Both marine and terrestrial hermit crabs can grow to large sizes. On some islands in the South Pacific, the hermit crab is the dominant species—these monstrous crabs are called coconut crabs, and they are the only species of hermit crab that does not need a shell to live in.

What a Hermit Crab Needs

The right enclosure. The first thing you need to do is figure out what size tank you can get. Hermit crabs are social creatures and often feel better when housed in groups. You want to make sure that you are not overcrowding your tank. I have a 10-gallon tank, and I house three hermit crabs. Remember, even if you start off with small crabs as they molt they will grow, so do not fill your tank with a bunch of small hermit crabs.

The right substrate. Once you've decided on a tank size, you will need to fill it with a substrate. There are a lot of different kinds of substrate out there, so just look around and see what will be the best fit for you and the little crabs. Now that you have the tank lined with the substrate, you will need to add decorations. You will also need a place for the hermits to hide and feel safe, a bowl for food, and a source of water.

Choosing and Laying Your Substrate

There are a lot of different substrates marketed for hermit crab use. Honestly, you can use nearly anything that is safe for use with reptiles. I personally like to have a layer of sand at the bottom. I typically use hermit crab sand as it has extra calcium in it, which is always helpful for invertebrates. I also like to have a layer of fine coconut fiber, and I like to have a blend of coconut fiber and wood chips on the top. To me, this combination looks natural and allows the hermit crabs to experience different textures as they dig around.

Add Water?

Some substrates, like fine coconut "dirt," will need water added to them to get reconstituted. This also helps to add humidity to the enclosure. Some cheaper sands and coconut fibers may stick to the crabs.

How Deep?

No matter what substrate or combination of substrates you decide to go with, make sure that you have a nice thick layer. A few inches will allow for the crabs to be able to dig. Many crabs like to bury themselves before they molt, so being able to dig is important.

Humidity, Temperature, and Water

  • Humidity. Terrestrial hermit crabs need a high level of humidity to survive. This is because they have gills (you cannot see them because they are covered by their shell). Having substrates that hold in water will help to increase the humidity inside the enclosure. Also, using a spray bottle to mist the substrate, or a sponge, will also help to increase the humidity.
  • Temperature. Hermit crabs typically come from tropical and subtropical environments. This means that they require temperatures a bit above standard room temperature. To help keep the temperature of the tank in the mid-70s, you can use a heat lamp, and under tank heater, or a heating pad that sticks to the side of the tank. Just make sure that you only have the heating element on one side of the tank because the crabs may get too hot and want a place to cool off.
  • Water. Your terrestrial hermit crabs need access to fresh water. Make sure that you are adding something to remove chlorine from your tap water or use bottled water. Chlorine is harmful to hermit crabs and could kill them. The hermit crab will also need access to a saltwater 'pool' so that it may soak.

In my tank I have a small shell with a sponge that I spray each day to keep my humidity up, I have a fresh water bowl, and a bowl of salt water. I also have a heat lamp and a heater that sticks to the side of my tank. Honestly, I only really have to worry about the temperature in the winter as the room the hermits live in has a lot of natural sunlight and is always warm.

Why Is My Hermit Crab Slow and Inactive?

If you notice that your crabs are not very active, you may want to check the temperature of your tank. If it is too cold, their metabolism may not be very fast, which will cause them to be sedentary. Many pet stores sell a thermometer that sticks to the side of a glass or acrylic tank.

Habitat Enrichment and Decor

It is important to have decor in your hermit crab tank. This will allow them to explore their home and give them exercise. You will also want to give them a dark place to cool off, hide, and feel safe.

Before you add any sort of decor to your hermit crab tank, you will want to rinse it with hot water and allow it to dry. This will help make sure that you are not exposing your crabs to any contaminants.

Personally, I am a fan of natural-looking decorations, but you can get everything from real wood to glow-in-the-dark plastic sticks. I try to give my hermits different layers of decor, this way I am making the most of my smaller tank and allowing them plenty of places to explore.

Other Things a Hermit Crab Will Need

A place to climb. Hermit crabs can and will climb. They have been known to use the lining on the corners of fish tanks to climb. This means that you will need a lid for your hermit crab enclosure.

Proper food. Hermit crabs, like all living animals, require food. Yes, you can get pellets for your hermit crabs at the pet store. And yes, you can buy all-natural organic hermit crab food on Amazon. However, you don't need to go all out. I keep a small bowl of pellets in my crab tank, and each time I make dinner, I add little bits of the fruits or veggies I use. I've found that my crabs really like zucchini. I also give them small shrimp sometimes as treats. Remember, hermit crabs are omnivores and will each whatever they can, including wood. They also do not need a lot of food as they are quite small.

Calcium. You can add a calcium powder to the pellets or veggies, and this will help the little hermits get all the calcium they need.

A variety of shell options. Hermit crabs have an exoskeleton and will periodically molt and grow a new exoskeleton. When hermit crabs molt, they typically grow larger, and this may mean that they will outgrow their current shell. Make sure that you have a variety of shells of all sizes for your hermit crabs to choose from. I've seen crabs that have forced another crab out of a shell because they didn't like what was available to them.

Do Hermit Crabs Pinch?

Hermit crabs can make wonderful pets, and they are so much fun to watch. If you have small children, please remember that they do have a rather strong claw. I worked at an aquarium for over 3 years and was never pinched by any of the frustrations I worked it, but I've been pinched many times by my own hermit crabs. I can tell you it hurts.

If you are afraid of handling the hermit crabs, it is probably best that you do not. Once they pinch they will not let go until they want to and if you drop them they could be badly hurt or even die.

I love watching my hermit crabs move around. I love when they come out of their shell and come over to say hello. I think their little faces are adorable. I always get so excited when my hermits molt and change shells. These little guys are less work than an aquarium (you don't need to worry about water chemistries), and great for people that want a pet but don't have a lot of room or the ability to go on walks or expensive vet bills.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

Questions & Answers

Question: Can I use rocks for my hermit crab?

Answer: If you are asking if you can put rocks in with your hermit crabs the answer is yes, keep in mind they will take up space in the tank. If you are asking if the hermit crabs will be able to use the rocks for home the answer is no, they will only be able to use shells.

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