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8 Simple Ways to Keep a Hermit Crab Tank Humid

8 Simple Ways to Keep a Hermit Crab Tank Humid

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The purpose of this blog is to share general information and is written to the author's best knowledge. It is not intended to be used in place of veterinary advice. For health concerns, please seek proper veterinary care. In addition, as an Amazon Associate I earn from qualifying purchases.

Hermit crabs are very interesting pets, but it’s crucial to learn how to care for them properly. If you don’t meet the hermit crab’s needs, then it isn’t going to live a happy life in your home.

You need to be sure that you set up a tank for the hermit crab. The tank is also going to need to have everything that the crab needs.

One aspect of keeping a hermit crab tank that intimidates newcomers involves humidity. The tanks need to maintain a certain humidity level so that the crab can thrive.

How do you go about doing this? Continue reading to learn more about this topic so that you can have the best experience caring for your pet hermit crab.

Why Is Humidity So Important for Hermit Crabs?

You might not be aware of this yet, but hermit crabs don’t have lungs. They have gills, but the gills are modified to allow them to live on land.

A hermit crab is able to breathe because of moisture. If moisture isn’t present in the air, then the hermit crab isn’t going to be able to breathe normally.

This means that a hermit crab habitat must maintain a certain humidity level. Failure to do so could wind up killing the poor hermit crab.

Since you want to do your best to care for the pet, you’re going to need to focus on getting the humidity right in the hermit crab tank. This is considered to be the most important aspect of caring for hermit crabs, and it even matters more than what you feed the crabs.

1 – Make Use of Natural Sponges

Natural Sponges

The best thing to do is to make use of natural sponges. You can purchase natural sponges from aquarium stores, but they will also be available for purchase at various household supply stores.

When you have what you need, you’ll want to soak the sponge in freshwater. Ensure that the water is dechlorinated so that you don’t harm the hermit crab.

This will help to provide humidity in the hermit crab’s tank. It’ll also be good because it’ll give the crab something that it can use when it feels as if it has become too dry.

Of course, the sponge isn’t something that you can ignore for weeks on end. You’re going to need to replace the sponge with a new one every single day.

Failure to do so could lead to the sponge having issues with fungi and bacteria. This can be very harmful to the hermit crab, and you need to avoid such complications.

When replacing the sponge, you’re going to need to take the old one out. Sterilize the old sponge so that you can use it again another day.

Sterilizing sponges will be very easy once you get used to what you’re supposed to do. Simply boil the sponge in dechlorinated water for fifteen minutes and everything will be fine.

2 – Install a Humidity Gauge in the Hermit Crab Tank

Installing a humidity gauge in the hermit crab tank will be a good idea. This will allow you to glance over and see if the humidity is at an acceptable level.

You should be mindful of the humidity gauge at all times. A day shouldn’t go by where you don’t check the humidity gauge to see how everything looks.

Take daily readings and ensure that you don’t allow the tank to drop below seventy percent humidity. If you see that the tank has lower humidity levels, then you’ll need to add moisture to the tank as soon as possible.

Consider a humidity level below seventy percent an emergency situation. You’ll need to take measures to increase the humidity right away since the hermit crab’s ability to breathe will be impacted.

To add moisture to the tank, it’s recommended to mist the tank with dechlorinated water. This will raise the humidity, and it should help you to get things under control.

Another option is to put shallow bowls of water in the tank. You could use this as a way to provide ample moisture if the level is very low.

It should also be known that simply adding another wet sponge to the tank can help. If you have many sponges that you can use, then there might be some merit in keeping two sponges in the tank.

This really depends on the humidity levels in your area. If you live in a dry climate, then you might need to do more to raise the humidity level so that your hermit crab can thrive.

3 – Hermit Crabs Need Both Fresh Water and Salt Water

Hermit Crab in Water Bowl

It should be noted that hermit crabs need both fresh water and salt water. You’ll be adding a shallow bowl of dechlorinated water to the tank, but you should also have a salt water bowl in there.

The hermit crabs should be able to soak themselves in the water bowls. The bowls need to be shallow enough that the hermit crabs will easily be able to get out of them.

Otherwise, the hermit crabs could easily drown. Try to use bowls that are wider than they are deep, but make it so that the hermit crab will be able to fully submerge itself in the water.

Hermit crabs will choose whether they want fresh water or salt water. It’s good to give them the option because they will want to use both at various times.

The bowls will help to raise the humidity levels of the tank, but they’re also there simply for the health of the hermit crabs. If you do a good job of picking out the bowls, then the crab will be able to live much more happily.

To make the bowls of water, you’ll want to buy distilled water to use in the fresh water bowl. You can treat the other bowl of water with pet supply salt.

4 – Add Moist Moss to the Tank

Adding moist moss to the tank is something that many hermit crab enthusiasts do. It’s a good idea because it’s a practical way to increase the humidity level in the tank.

Aside from this, some feel that having moss in the tank makes the habitat look cooler. It can add something to the overall aesthetic appeal of the tank.

You don’t absolutely have to do this, but it’s something that can help. Also, moistening moss is a fairly easy thing to do.

Your hermit crab will appreciate the effort that you’re going to. This is just another helpful thing that makes it easier to keep your hermit crab healthy.

5 – Airstones Can Be Useful

Have you thought about purchasing an airstone? For those who don’t know, airstones are commonly used in fish tanks.

These are stones that are placed in the water, and they gradually diffuse air into the tank. They’re good for helping to keep fish healthy.

So why is this something that would help your hermit crab? Well, you’d be placing the airstone in a bowl of water, and then you’d place that into the crab’s habitat.

Switch the airstone on and it’ll make sure that more water evaporates. This raises the humidity level in the tank quite a bit.

Doing this is going to be better than simply placing a shallow bowl of water in the tank. It’ll be an especially useful thing to remember if you’re trying to keep a pet hermit crab while living in a dry area.

6 – Ensure That the Crab Has a Proper Habitat

Large Empty Fish Tank

Ensuring that the crab has a proper habitat will make it easier to maintain moisture levels. You want to keep a pet hermit crab in a glass aquarium of some sort.

Most people choose to keep hermit crabs in 10-gallon glass aquariums. Such an aquarium will comfortably house two hermit crabs if you want your pet to have a friend.

If you make the mistake of keeping a hermit crab in a wire mesh cage, then things won’t go well. You won’t be able to trap the moisture at all.

A glass aquarium is perfect for trapping moisture in the habitat. You can even enclose the cage using a glass or hard plastic top to trap more moisture inside.

If you have an aquarium with a wire mesh top, then you could simply stretch plastic over the top. This is a good solution when you want to keep the moisture in the tank without allowing it to escape.

7 – Add Houseplants to the Room

Adding houseplants to the room will be a good way to raise the humidity level in the room. If you’re living in a dry area, then it’s likely that your home is fairly dry.

This can irritate your skin, but it’ll be much worse than an annoyance for your pet hermit crab. Thankfully, keeping houseplants will be a satisfying way to raise the humidity level of your home naturally.

Simply pick out some houseplants that you find to be appealing. It’s likely a good idea to pick houseplants that are beginner-friendly if you don’t have much experience caring for plants.

Keep caring for the plants and do your best to keep them alive. You should be able to raise the humidity level in the room quite a bit.

8 – Buy a Humidifier


If your home is very dry, then it’s likely going to make sense to buy a humidifier. A humidifier will ensure that your home is humid enough, and you won’t have to worry quite so much.

There are many different types of humidifiers on the market. Some of them are designed to humidify the entire house, but others will be more useful for humidifying single rooms.

Depending on the situation, you might need a small humidifier or you could need a large one. Measure the humidity level in your home to see how things look.

This should help to inform your decision. You’ll then be able to buy what you need at a department store or you can order a humidifier online.

Of course, you can’t let the humidity get too high in the house. Ideally, you want the humidity level to be between forty and fifty percent at the highest.

When humidity levels reach sixty percent and above, it can lead to issues with mold. You don’t want to have to deal with this, and that means you don’t have to go overboard with raising the humidity in your home.

Simply having an average humidity level in the room that the hermit crab is kept in will make it easier to raise the humidity in the crab’s cage. It ensures that the baseline humidity of the room isn’t too low, and you’ll have a better time caring for the crab as a result.

Final Thoughts

Taking care of your hermit crab properly will allow you to enjoy your time with it. If you don’t pay attention to the humidity level in the tank, then your new pet isn’t going to survive very long.

Even if you don’t live in a dry area, you’re going to need to take steps to raise the moisture levels in the tank. This means that you should mist the tank a few times per day while also replacing the moist sponge on a daily basis.

Yes, this does mean that you have to be a fairly proactive pet owner. If checking on your pet hermit crab at least once per day seems to be too much work, then it’d probably be unwise to purchase one of these creatures.

Thankfully, keeping the humidity level in the hermit crab’s tank at the right level isn’t that hard. Placing a hygrometer (sometimes referred to as a humidity thermometer) in the tank will allow you to keep an eye on things.

Always keep the humidity level above seventy percent and everything will be fine. If you’re using all of the methods outlined above, then it shouldn’t be tough to keep the humidity in the proper range.

Use this information to decide whether having a pet hermit crab is right for you. You shouldn’t be intimidated or think that caring for a hermit crab will be too tough, though.

You just want to know that you have enough time to take care of the crab properly. So long as you do, it’ll be easy to get good results.

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