Keeping Hermit Crabs Warm: Everything You Need To Know

I’m writing this article in July 2019 and it feels like the year has flown by. It’s hard to believe winter is only 3 months away. With that comes the cold and another chore for my hermit crabs: keeping them warm.

It’s hard to think about this during the summer, especially when the Midatlantic (where I live) is expected to see record high temperatures this weekend. Tomorrow’s a high of 98 F and humid! Wow! I might have to write a post on cooling down hermit crabs.

But like I said, winter isn’t far away, and every good pet owner is always prepared.

Let’s get into how to warm your land hermit crabs and keep their enclosure a comfortable 65-80 degrees Fahrenheit (19-27 degrees Celcius), with at least 70% humidity.

What I do to keep my hermit crabs warm.

What works for me in keeping my hermit crabs warm are two under the tank heating pads. I used to have one, but I had to upgrade to two once I moved from a 10-gallon to 40-gallon hermit crab tank. They stick on the tank like a sticker, but I’ve found that the heat removes the sticky-ness overtime. I just use duct tape to keep it on! I don’t mind because they’re so cheap, feel free to check this out on Amazon (affiliate link).

Here’s my first heater on my old tank. I’ve since bought another when I upgraded to a 40-gallon tank. I put it on the side rather than beneath the tank so my hermit crabs would hang out on the surface more.

You’ll quickly find out that hermit crabs love to hang out by the heater. Here’s a picture I took of my crabs chilling by mine.

One thing I don’t like about a heater is that it dries out the substrate around it, so you’ll have to spray it with your spray bottle more often. Other than that, it’s important for maintaining a temperature above 65 degrees F in your hermit crab environment.

First, buy a thermometer

Before you can even think of heating your hermit crab tank, you need to know what temperature your hermit crab tank is at. This will alter you if your hermit crabs environment drops below the recommended 65 degrees F.

I recommend buying a thermometer that can attach itself to the side of your hermit crab enclosure. It needs to run low enough to the surface of your substrate (where your crabs spend most of their time) to get an accurate measure of your crab’s environment.

If you don’t have a thermometer yet, I also recommend buying one that comes with a hygrometer (a device that measures humidity).

I bought this Thermometer and Humidity Gauge on Amazon (Affiliate link to Amazon) back in August, 2021. It replaced my old one that stopped working after a few months of use. I didn’t expect much from this since it was so cheap, but it’s continued to run and stay accurate since I bought it!

3 ways to keep your hermit crabs warm with electricity

The three easiest ways to keep your tank mild and cozy need some help from our old pal electricity. Let’s look into each one and how it’ll keep hermit crabs warm and snug.

1) An under the tank heater

A widely-known favorite method to keeping the little critters warm in the hermit crab community is an under the tank heater.

These look like a thin heating pad, which it is, but specifically designed for reptiles or, in this case, crabs.

They work best for aquariums or any sort of tank (not the wire mesh or plastic containers hermit crabs come in). They can be either secured to one side of the tank or the very bottom.

Where you place it is up to you as long as you keep the heat on one end of the tank. Hermit crabs need to be able to move wherever they feel most comfortable.

If the heater is under one end of the tank or along one wall of the tank, they can feel free to move wherever has a comfortable temperature. That may mean burrowing into the substrate closer to the heater or huddling along one wall.

Keep in mind that these things get warm. Most heating pads designed for hermit crabs heat up to around 85 degrees F.

Since my temperature has read a steady 70-80 degrees Farenheight for the past month or two I’ve had my crabs, I haven’t needed to buy a heater just yet.

Even so, I spent multiple hours researching products and asking close friends for their opinion on the best hermit crab heating pad. Everyone said the same thing.

So, just yesterday I threw it in my cart on Amazon and it was shipped right to my door. I couldn’t be happier with it! Click here to check out my review on the product, why I bought it, how to set it up, and its pros and cons.

2) A heat lamp

If you’re worried that a heating pad isn’t enough to keep your hermit crabs warm, try a heat lamp.

In this case, we need a bulb that will do two things: provide daytime light and heat.

For this, you can use either an incandescent white light bulb, a reptile daylight heating bulb (incandescent), or a UVB CFL with a heating element.

You’ll have the most luck shopping for an incandescent white light bulb. You’ll find one at most pet stores and sometimes at hardware stores. If not, look for a reptile heating bulb. UVB CFL bulbs with a heating element are a great choice but can get pricy.

You will need a certain wattage light bulb depending on the size of your tank, the amount of heat needed, etc. There is no way to say X amount of watts will raise your tank by Y degrees, which makes the bulb you need a guessing game.

My advice: go with a 25-50Watt white bulb and adjust how close/far away it is until your thermometer reads the perfect temperature.

There’s so much I could tell you about heat lamps I could make an entire article. Hermitcrabssociation.com did an amazing job explaining everything there is to know about heat lamps. Check out their article here.

Just a fair warning that using a heat lamp is a hit or miss when it comes to warming your hermit crabs. The light fixture has to point a certain way and heat a certain side of the tank.

There’s a lot of variables involved, which makes for a complicated solution for a simple problem. My advice: go with the heating pad.

3) A humidifier

A humidifier is a great option for your hermit crab enclosure because it kills two birds with one stone. Not only does it bring plenty of warm air into the tank, but it also increases its humidity.

I don’t have one personally, but after doing some research I’m interested in buying one. I live in a rather humid area, but I still gotta do some work to keep my tank’s humidity around 75%.

I keep my tank humid with my handy spray bottle, some sponges, and a bit of moss. It keeps the tank humid but it’s a lot of work.

With a humidifier, all I have to do is plug it in. I found a great reptilian humidifier on Amazon (click here to check the price) that would work just as well for hermit crabs.

The only chore that comes with a humidifier is refilling the water. With the item I found above, this will be around every 3 days on the medium setting. I believe this is just enough for a 20-30 gallon hermit crab tank. With any less/any more space, you will have to increase/decrease the humidifier’s output.

If you’re feeling crafty you can DIY your tank’s humidifer. Check out this Instructables article I found on making a $10 hermit crab humidifier.

The creator ingeniously took a bubbling rock (a tank decoration that can be dangerous for hermit crabs) and turned it into something to help the crabs without endangering them.

5 ways to keep your crabs warm without electricity

Say, for example, you need to temporarily keep your crabs warm and you don’t have access to any electricity. This could be from a power outage, a long car trip, etc.

No matter the case, I found 5 ways to keep your crabs warm and cozy without any fancy electrical gadgets.

Note: These methods do increase your crabitat’s temperature, but they can not replace a tank heater or heat lamp. They can keep a hermit crab’s tank at optimal tempeature for a short period of time, but they require much more work.

1) Move your crabs to a warmer spot.

I understand that this is a very obvious method, but I thought I would add it anyway.

It’s easy for new hermit crab owners such as my self to overlook the obvious when it comes to keeping their hermit crabs warm.

Moving your crabs away from an open vent, a window, or anywhere that can let in a draft can significantly impact your crabitat’s temperature.

I recommend keeping your crab’s in a room without any drafts or open windows during the colder months. This will keep your hermit crab enclosure warm and humid on cold days, especially when you use the other methods mentioned in this article.

2) Add extra substrate.

It’s common knowledge across the hermit crab community that hermit crabs need at least 4 inches of substrate in their tanks. This can be a mixture of play sand and coconut fiber or entirely coconut fiber for simplicity’s sake.

This substrate accomplishes two things: it holds moisture in the soil and allows your crabs to burrow.

Holding moisture is fantastic because it keeps your crab’s tank humid. Hermit crabs love humid environments.

Allowing your crabs to burrow is even better because it allows your crabs to stay warm. When they burrow in the substrate, it acts as a warm cozy blanket that keeps the heat they radiate from escaping.

This is made possible by a little phenomenon called insulation. In the wild, animals with fur use insulation to keep themselves warm in colder climates. Their fur acts as a roadblock to escaping heat, keeping their bodies warm.

3) Spray warm water.

Continuing with clever ways to keep crabs charged, I think this is the smartest trick yet.

Most hermit crab owners spray their tanks with non-chlorinated water to keep the humidity in their tanks high.

A handy way to keep your crabs warm and humid at the same time is to boil the non-chlorinated water for a few minutes before spraying it. After given a few minutes to cool, the boiled water will dramatically increase your tank’s temperature after being sprayed.

This is an outstanding way to keep your crabs warm and active, especially in the cold winter months.

4) Use towels or blankets.

With this method, we’re going to piggyback on the idea of insulation in method two. But this time we’re going to insulate the entire tank instead of just your hermit crabs.

You can accomplish this by wrapping the outside of your crab’s enclosure in one, two, maybe even three towels or blankets. This prevents any heat or humidity from escaping your crab’s environment.

Keep in mind that you need to leave an opening at the top of your crab’s environment for light and fresh air to enter the cage. By not doing this you risk messing up your crab’s sleep schedule or (even worse) suffocating.

5) Use hand warmers.

This is my favorite temporary solution for keeping crabs warm during a long car trip.

It’s simple. Buy a dozen hand warmers from the store (they’re dirt cheap!) and throw one or two in your hermit crab environment.

These work especially well when paired with method #4. Wrap a few towels or extra blankets around your crab’s tank and it’ll stay warm for hours. With the heat given off by the hand warmers and blankets working as insulators, your hermit crabs will be sure to stay warm and active.

What not to use for heating

Now that you know what you should use to keep your hermit crabs warm, let’s get into what you shouldn’t use.

Heat Rocks

Heating rocks are a big no-no all across the hermit crab community. These seemingly harmless stones which make fantastic bubbles when thrown in some water can be very dangerous for your hermit crabs.

They become dangerously hot very fast, and all that heat is centered in one spot on the rock. This can make it very easy for an unsuspecting hermit crab to step on the rock and burn its foot. It’s easy to burn yourself if you don’t feel any heat radiating off something hot!

Heating Pads

Heating pads and under the tank heats, what’s the difference?

It may be easy to think you can just take your old heating pad and use that to warm your crabs. This is a common misconception among new hermit crab owners.

It turns out that heating pads get too hot for your hermit crabs. They can melt the plastic decorations in your crabitat and have been known to slowly bake hermit crabs to death. They are designed for humans, not hermit crab tanks.

I recommend going with the under the tank heater. It’ll only put you out around $15.00, and is a much safer option for your hermit crabs.

Do not overheat your hermit crabs!

The last thing you want to do is make your hermit crab enclosure too hot or too cold. I mentioned this before, but an ideal temperature for your hermit crab enclosure is 70 to 80 degrees Fahrenheit.

If your crabs start to experience very hot temperatures, you’re in a world of trouble. Anything over 80 degrees F. is risky business. Staying above this temperature for prolonged periods of time will cause your crabs to overheat.

A clear indicator of overheating is if your crabs discharge brown liquid from their mouths. If you ever see this, take immediate steps to cool down your crabs. Overheating is a slow and painful death for a hermit crab.

On the other hand, if your crabs experience cool temperatures (50 to 65 degrees F.) for long periods of time, dormancy and hibernation will occur. This is not a good thing, as hibernation may permanently affect a hermit crab’s behavior and sleep schedules. This leads to unhealthy behavior and inactiveness.

Even worse, hermit crabs that are exposed to temperatures that fall below 50 degrees Fahrenheit for long periods of time will end up dying.

It’s important to keep your hermit crabs warm, but not too warm.

Do you need to worry?

Sometimes you don’t need to worry about your hermit crab’s temperature.

I’m not saying that you shouldn’t buy a thermometer and keep an eye on your crab’s temperature, I’m saying that sometimes certain circumstances don’t make it necessary to warm your hermit crabs.

For example, for climates don’t warrant the need for heating hermit crabs. Warmer states such as Florida, parts of Georgia, etc. are relatively warm for most the year.

You shouldn’t have to keep your hermit crabs warm in these states.

It can also depend on the season! Hermit crab owners only have to worry about keeping their crabs warm during the cool, winter months. Even then, it sometimes isn’t an issue because they use a heater.

I believe hermit crab owners tend to overthink their little guy’s care and spend way too much time fussing over what they’re doing wrong as an owner. I’ll tell you from experience that hermit crabs can be very low maintenance pets as long as you provide them with a good environment as well as plenty of food and water.

The key takeaway here is: keep an eye on your crab’s thermometer. If it gets too cold too often, but a heater. If it’s too warm, lay off warming your hermit crabs until the temperature settles down.