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Do Hermit Crabs Need A Heat Lamp?

When deciding to get a hermit crab, or after you’ve already purchased one (or a few) you’ll need to get a good enclosure set up. There are so many things to consider, such as substrate, food, size of the enclosure, humidity, and heating.

Hermit crabs come from tropical beaches and like it to be warm and humid. In fact, they need warm temperatures and humid air to breathe and survive. Most hermit crab setups require some kind of heat in their enclosure.

With so many heating options available, let’s take a look at heat lamps. Here we will go over everything to do with heat lamps. Is a heat lamp a viable option, is it necessary, what are the pros and cons, and if so, what kind should you get?

How Warm Does Your Hermit Crab Need To Be?

Hermit crab with yellow eyes in terrarium
Hermit crab with yellow eyes in terrarium

Depending on the species of hermit crab you purchased or are about to purchase, your crab could come from the Caribbean, Ecuador, Oceania, or other tropical climates. When setting up your enclosure, you’ll have to replicate these conditions as much as possible to keep them healthy and happy.

The ideal temperature ranges fall between 75 to 85°F during daylight hours and between 65 and 75°F at night. If the temperature falls below 62°F, your hermit crab could start to go into a hibernation cycle, or it could cause permanent damage.

Signs Your Hermit Crab Is Too Hot

Even though hermit crabs like it hot, if the temps climb much higher than 85°F your hermit crab could suffocate, or perish. It’s very important to monitor the temperature of the enclosure, especially when first starting it up.

If you happen to see bubbles on your crab, especially if they are brown, or you smell something fishy, or musty, these are clear indications that it’s either too hot in there, or your crab is severely ill.

Other signs your hermit crab is too hot are increased signs of activity during the daytime. Hermit crabs are naturally nocturnal. They tend to hide during the heat of the day while predators are about and come out in the dark to feed and explore.

Captive hermit crabs don’t always follow this rule though and may be more active during daylight hours. If you see yours scampering around more often than usual, or in extreme cases, coming completely out of its shell in a desperate attempt to cool off, it may be too warm in the tank.

Do You Need A Heat Lamp For Your Hermit Crab?

Hermit crab in an enclosure
Hermit crab in an enclosure

The straight up answer is no, you don’t need a heat lamp for your hermit crab, but it will need some type of heat source to maintain the tropical temperatures. Ultimately, the choice is yours and if you feel a heat lamp is the best way to warm the enclosure you can do so. First, though, let’s go into detail about heat lamps.

Hermit crabs, like nearly all animals, need a light and dark cycle to stay healthy. If you’re using a heat lamp, you will have to set it on a timer, or manually turn it off every night. Hermit crabs are happiest when they get 12 hours of light and 12 hours of darkness.

Depending on how warm the room is at night, you may still need a source of heat at night, especially in the colder months, or if the room gets chilly in the evening.

Pros And Cons Of Heating Lamps For Hermit Crabs

As we mentioned before, hermit crabs need a natural light and dark cycle, and a heating lamp can provide that. When an enclosure is in a dark room, one with no windows, or a basement, you’ll need a source of light. Heating lamps can provide that.

If you’ve used heat lamps before on other pets such as turtles, or other reptiles, then you may want to use what you’re comfortable with, which is fine. Heating lamps can provide light and warmth for hermit crabs.

If you opt for a heating lamp, look for a low wattage lamp, and always use a thermometer to monitor the hermit crab’s home. Don’t let any cords dangle into the enclosure, because as you may know, hermits are excellent climbers. They could use the cord to make a great escape.

You may also need to mount the lamp higher so that you don’t cook your little hermits. Adjust the height of the lamp, and subsequently the temperature as needed.

Another reason you may want a heat lamp is to provide UVB rays. Hermit crabs require a lot of calcium, and UVB rays help produce Vitamin D, which is essential in calcium absorption. Some heat lamps can provide this, especially in dark rooms where natural sunlight isn’t available.

Heat Lamp Cons

Artificial light can be stressful for hermit crabs. They have very sensitive eyes and are not accustomed to artificial lights, especially if they are very bright. Hermit crabs have excellent low light, or night vision, and can see very well at night, so they don’t need a bright light.

As we mentioned before, electric lights will need to be put on a timer. In very extreme cases, if hermit crabs can’t escape the light, and they’re too bright, or on all the time, they may resort to cutting their own eyestalks off.

This is an extreme reaction, but too much light really does cause a lot of stress to these little crustaceans. While hermit crabs can regenerate claws and limbs, they may not be able to regenerate their eyes.

Heat Lamps May Get Too Hot

Most heat lamps you find at the pet store are made for reptiles. Bearded dragons, tortoises, and some snakes need a very hot area and a cooler area. These lamps are made specifically for these pets, so they aren’t particularly great for hermit crabs.

You’ll have to monitor the temperatures heat lamps put out if you go that route.

You May Need Supplemental Heat At Night

When you use a heat lamp, you’ll have to turn it off at night so the hermit crab has a natural light and dark schedule. If the room it’s in gets cold at night, you’ll still have to provide a nightly heat source.

Instead of opting for a heat lamp, you may want to try a ceramic heater that does not produce light but will supply a constant supply of heat. These come with risks too though. Ceramic heaters will last much longer than heat bulbs, but they can also produce much more heat.

You’ll have to place these farther away from the tank so it doesn’t get too hot.

Heat Lamps Remove Humidity

Hermit crabs need a very high humidity level. Heat lamps and ceramic heaters can quickly dry out the warm side of the tank and could dry out your hermit crabs. They need such high humidity to keep their gill moist and breathe.

You’ll probably have to mist the enclosure daily, or multiple times a day to make sure it stays in the correct range.

How to keep hermit crabs warm without a heater

Natural environment

If you’re lucky enough to live in a tropical, balmy climate such as Hawaii, the Bahamas, or a similar area, you probably won’t need to provide a heat source for your hermit crab. Lucky you! Alternatively, if you have the tank in a room that stays in the ideal temperature range, you probably won’t have to add supplemental heat.

Heating pad

Tikaton Reptile Heat Pad - Adjustable Temperature Under Tank Heater for 10-20gal/30-40gal Tank, Terrarium Heat Mat for Turtle/Snake/Lizard/Frog/Spider/Plant Box

If you don’t have those luxuries, then you’ll need to use something to keep it warm enough for these crustaceans. An under the tank heater (UTH) is the best option for hermit crabs.

These are flat pads with an adhesive side that you stick to the outside of the enclosure. Though they are named “under the tank” for hermit crabs, they need to be placed on the side of the tank.

Hermit crabs require a thick layer of substrate, and putting a heater at the bottom of the tank will get it too hot for them. When they go to molt, the hot substrate could kill them. Also, they can be a slight fire risk if they are placed underneath all that substrate.

Technically it’s not a heat lamp, but the Tikaton Heat Pad – Adjustable Under Tank Heater for 10 – 20 gal may be the ideal tank heater for your hermit crab. This heater is the perfect size for most “crabitats” as it fits 10 to 20 gallon tanks, and it has an adjustable thermostat. All you have to do is stick it to the side of the tank, plug it in, and monitor the temperature until you get it perfectly dialed in.

What About Natural Light And Heat?

Rooms that have plenty of natural sunlight and are warm enough that you don’t need a supplemental heat source are great. Just a word of caution, be sure you don’t place your hermit crab enclosure directly in a window. This is especially true if the window gets the intense afternoon sun.

When sunlight glares through the window, and then the glass of a hermit crab tank, the rays get amplified. The result could be a hot box that quickly cooks your little crabs. Yes, sunlight is best, but let them get ambient light instead of direct, amplified sunlight.

Again, hermit crabs are sensitive to very bright light. They don’t have eyelids, and the only way to get away from too much light is to withdraw into its shell, burrow, or find a place to hide.


How do I know if my hermit crab is too cold?

Since hermit crabs are cold-blooded, the first sign your hermit crab is too cold, with be a remarkable decrease in movement and energy. They will become lethargic. Unfortunately, when it comes time to molt, they can also become lethargic, as well as if they are sick.

If they stay too cold for a longer period, hermit crabs can also start dropping their legs. Leg dropping means they will remove some of their legs. If hermit crabs are very stressed, fighting, or too cold they can leave behind a leg or two.

Keeping a quality thermometer in the crab tank is the best way to make sure your hermit crabs don’t get too cold, or hot. Get into the habit of constantly checking it. Look at it when you’re feeding them, cleaning the tank, or any other time you’re tending to your pets.

How do I cool off a hot hermit crab tank?

Sometimes you may find that your hermit crab tank is approaching the too warm mark (over 85°F). When this happens you need to cool it back down safely, but you don’t want it to get too cold. First, check to make sure the heater isn’t malfunctioning, or the tank is getting too much sunlight and fix that issue. Next, point a fan at the tank and turn it on.

The cool air should safely cool off the tank. If you need faster cooling, or the fan isn’t working as well as it should, you can also mist the tank with cool, unchlorinated water.

Can I use a heating rock in my hermit crab tank?

Heating rocks can be great for snakes, and some lizards, but they should never be used for hermit crabs. Heating rocks can get too hot, and may even have a small very “hot spot” that can cause your crab to burn. Don’t use heating rocks for hermit crabs, the best heat source is an under the tank heater, placed on the side of the enclosure.

The Verdict

Remember that hermit crabs come from tropical climes when you’re setting up their habitat. You’ll want to recreate that environment as closely as possible.

They need warm temperatures, especially during the day, at night the temps can dip slightly. Hermit crabs also need plenty of humidity so they can breathe through their gills.

Heat and lighting are extremely important for hermit crabs, but artificial light, especially when it’s very bright can be stressful for them. Natural light is best, but it’s not always an option. You can use a heat lamp to mimic the natural conditions with a few caveats. Closely monitor the temperature and adjust as needed, use a low wattage bulb, and make sure you continue to provide plenty of moisture.

When heating your hermit crab tank, a side mounted, under the tank heater is your best option. It doesn’t get too hot, it won’t dry the tank out quickly, and it can be kept on day and night if needed without bothering their circadian rhythm.

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