Hermit Crab Heating and Lighting Requirements Guide

Hermit Crab Heating and Lighting – Full Guide with Images

If you are setting up your hermit crab tank (crabitat), you might be overwhelmed with all the heating and lighting options. Are you looking for the most suitable heating and lighting options for your hermit crabs’ tank? If you are still unsure about the tank sizes and material, see this post first (new tab). In this post, you will learn all about hermit crab light requirements, heating and lighting at night, wattages, cycles, light bulb options, UVB requirements, heat sources, heat mats, ideal temperatures and much more.

Hermit crab lighting and heating requirements

Hermit crabs don’t have specific lighting requirements for the tank. If your room has enough light during the day and is warm enough during the day and night, then you don’t need to use a separate light bulb. That’s unless you need to heat the tank or want to watch your hermit crabs at night. There are a few lighting options for a hermit crab tank, which we will discuss later. But in general, please see the following points below:

  • Make sure the room with your hermit crabs’ tank has sufficient lighting. If it doesn’t, you will need to use a lighting bulb.
  • You will also need to provide a UVB source for your hermit crabs (will help with vitamin D production, calcium absorption, energy levels, coloration). Though it’s not mandatory, it is believed to improve the well-being of many organisms. UVB sources need to be replaced every 6-12 months. Any glass/mesh will filter UVB greatly.
  • Hermit crabs’ tank needs to be warm – they cannot thrive in a cool or cold environment.
  • Heating pads might cause problems if used inside the tank (burning hermies and creating air pockets). Be careful if you use one. There are bulbs that don’t produce light, so you can use one of those if you don’t need to light the tank.

Please make sure to set up lighting and heating before you bring hermit crabs home. You will probably need to make a few changes before everything is ready.

Hermit crab heating and lighting bulb options – explained

In this section, you will find heating and lighting bulb options. Depending on what your setup needs, you will be able to decide to choose your preferred options. Please note, that if your room temperatures are ideal for your hermit crabs, there’s no need to have a heating element for the tank.

Optimal temperatures for hermit crabs are 80-82 degrees F (26.6-27.7 C), with the minimum being 75 F (23.8 C), and maximum – 85 F (29.4 C). When installing and experimenting with heating and lighting options, always keep an eye on humidity levels (with a hygrometer). If they drop, mist the tank up to a few times a day. Humidity levels of 75-80% are optimal for hermit crab tanks. Make sure there’s a warm and cooler side in the tank.

If you want to light and heat the hermit crab tank

Option 1: Reptile daylight basking bulb – white, red, blue

Hermit Crab Heating and Lighting - Day and Night Options

There are different wattages, types and colors for reptile daytime/daylight basking bulbs. In general, these are incandescent bulbs and often come in white, red or blue colors (least hot). White bulbs are often the hottest, and produce more visible light. This is followed by red, and then blue bulbs.

If you want to heat and light the tank during the day, it’s better to choose a white colored bulb. Otherwise, other colors, especially blue, are pretty cool and can mimic evening time + not produce enough heat. An example of a daylight bulb would be this 50-watt white reptile daylight bulb.

An incandescent bulb will produce light and heat for your hermit crabs. Basking spot bulbs tend to get hotter than general daylight bulbs, so 50 watts might be sufficient for a 20-40 gallon tank. However, this might differ.

To use this kind of bulb, you will need to get a fixture, clamp or a dome like this, that you will screw your bulb into. If using a dome or a lamp clamp, you will be able to place it on top of your hermit crabs’ tank.

There are single and dual domes, if you want to add an additional bulb. There are often 5.5 and 8.5 and 10-inch domes – the larger the dome = higher the temperatures can reach in the tank. If your tank is smaller, go for the smaller clamp/dome.

Depending on your room temperatures and tank size, you will need to choose between various bulb wattages. If you are just setting up a tank, it’s always recommended to get a few different wattages and experiment (trial and error is always the part of a tank setup process).

Daylight incandescent basking bulbs don’t produce any UVB, so you might choose to get a separate 2.0-5.0 UVB fixture to run through the tank or an additional UVB bulb (no heat). UVB needs for hermit crabs are still discussed, but UVB is important for most living creatures for vitamin D synthesis, calcium absorption, mood, bone health and more. CFL would be a compact light bulb that also emits UVB.

Option 2: General home incandescent light bulbs

You can also use general incandescent light bulbs for home use. They will be bright and produce heat in the tank. If you don’t want to use general home bulbs, but have a few at home, you can test temperatures in the tank with these bulbs.

Because general incandescent lights won’t emit UVB either, you might choose to get a separate 2.0-5.0 UVB fixture or bulb (dual domes can accommodate two bulbs, or you can get 2 clamp-lamps).

Option 3: Mercury vapor bulb (MVB)

Hermit Crab Heating and Lighting Requirements - Full Guide

Mercury vapor bulbs are a great option because they emit both light and UVB. Many hermit crab keepers don’t have UVB lamps or fixtures for their tanks, but UVB is important. UVB will help produce vitamin D, absorb calcium, and well help with the activity and coloration of hermit crabs.

Mercury vapor bulbs like this produce visible white light and UVB, but they get rather hot. Only choose a 100 watt if you have a bigger tank (around 40 gallons or more). For smaller tanks, choose a 25-50 watt bulb. Mercury vapor bulb need to be replaced every 12 months or so, because it will stop producing UVB.

Option 4: Halogen flood bulbs

Halogen flood bulbs provide lots of light and heat, but no UVB. However, in the last years, halogen bulbs are getting replaced with other more energy-saving options. You can find flood bulbs for both reptiles and general homes if you wish to give them a try.

If you only want to provide your hermit crabs with light and UVB (if need heat, add a heat bulb)

Option 1: Fluorescent bulbs or fixtures

Another great option is to get a full-spectrum bulb or a fixture. You can choose between traditional or compact fluorescent lightbulb (CFL), like this 5% UVB compact bulb. CFL option is great for small or medium tanks, covering both light and UVB requirements.

5% UVB is generally enough for hermit crabs. Fluorescent bulbs or fixtures don’t produce heat, so if you need to heat the tank too, you’ll need to heat a heating bulb separately.

You can also choose to get a fixture, if you want a uniform distribution of light through the tank. A fixture runs through the tank, and should cover around 50-75% of its length (not 100%). If you want to get a fixture, measure the tank and choose the right-length fixture.

An example of a 5.0 fluorescent fixture would be this T5 ReptiSun fixture, which is also very popular among reptile keepers. T5 fixtures produce more UVB and light than T8 fixtures, which you can also explore instead. Please note, that you will have to replace UVB strips every 12 months, and bulbs – around 6-12 months.

If you only want to provide light only

If you don’t want to get a bulb that emits heat or UVB, you can choose LED bulbs. LED bulbs are efficient and use little energy, and also last for a long time. If you solely want to choose an efficient bulb, you can go for an LED bulb or strips.

If you wish to go for LED strips, you can get aquarium light strips to install on top of the tank. This would be better for larger tanks however. And then, if you wish, you can get a separate UVB option (5%, or at least 2% UVB).

When choosing an LED bulb, go for daylight, or at least soft daylight coloration (more yellow, can choose if hermits are sensitive to brighter lights you are using).

The light that mimics natural light is the best option. 6,500 Kelvins will produce natural bright light. Anything lower might be too dark. However, for nighttime viewing, lower color brightness is required.

If you want to provide heat only

Hermit Crab Heating and Lighting Guide - Wattages, Bulb Options Etc.
CHE

If you want to only heat your hermit crabitat, you can choose infrared bulbs, CHE bulbs or heating pads/cables. There are a few issues with using heating pads, but it can be done.

How to keep the hermit tank warm without a heater

If you want to keep your hermit crabs’ tank warm without a heater, you can try putting it in a warmer spot of the house. However, avoid any direct light hitting the tank, as it can cause serious temperature spikes in the tank. You can also insulate the tank by wrapping some towels around the tank.

If you have no electricity, you can keep your hermit tank warm by placing hot water bottles near the tank or using heat packs, hand warmers (or instant hot packs).

Hermit crab nighttime lighting or heating – infrared, CHE and blue/red bulbs

If you want to watch your hermit crabs at night, you can have a simple black, red or blue Moonlite bulb like this one. These bulbs will produce dull coloration (black is least bright, and might even be too dark) and should not disturb your hermit crabs in the tank. It will produce heat, so it might be a good thing if you need to heat the tank. But if you don’t need to heat the tank, you can choose a red or blue LED light, that won’t produce any heat, but don’t leave it for the whole night.

Another great option for night time heating is a ceramic heat emitter like this. This bulb is great for heating the tank, and won’t produce any visible light. CHE is great if your house gets cold at night.

Depending on how much temperatures drop at night, you might choose a 25 watt bulb to bump temperature by a few degrees in a small tank. There are 50, 75, 100 and even 150 watt options.

Another option for heating tanks at night is infrared bulbs. They produce enough heat and are suitable for various sized tanks.

Under tank heaters for hermit crabs

Hermit Crab Heating Pads - Good or Bad

Many hermit crab keepers tend to choose under tank heaters (UTH) or cables for their tanks. There are a few problems with using under tank heaters for hermit crab tanks. If using an under tank heater, placing it under the tank (outside) is not likely to keep the tank warm. That’s because of a thick substrate layer, the heat won’t go through.

If you place an under tank heater inside, under the substrate, it can lead to hot pockets in the substrate. As we know, hermit crabs love to burrow, so they can burn themselves. This doesn’t always happen, but is certainly a risk.

What is more, the main goal is to heat the air, not the substrate. There’s an option to mount the UTH to the side of the tank, but if there’s no gap between glass and UTH, it can lead to grass cracking.

If you decide to try a heating pad, you can mount it to the side of the tank, above the substrate level. This is important as you need to heat the air in the tank, not the substrate. However, this might not make it warm enough in some cases. Make sure that the heating pad is not as long as the tank, it has to cover only a part of the tank. But if the tank is not warm enough, you might try a bigger size. There has to be a warm and a cool side in the hermit crab tank though.

Most heating pads come with an adhesive, like this one, so you can stick to the tank. If it doesn’t, you will need to get an adhesive separately. However, if you decide to try using a UTH, make sure to put a layer of gravel or similar. You would need to prevent your burrowing hermits from touching the strip in any way.

Hermit crab light cycles

Hermit crabs are nocturnal, which means that they get active at night. However, their tank must be dark at night, just like naturally in the wild. If your room is well-lit during the day, you don’t need a light source for the tank at night.

But if you do use a bulb to heat or light your hermit crab tank, make sure to put it on a timer. This way, bulbs will turn off for the night. If you want to look at your hermit crabs at night, you can use a blue bulb, such as Moonglow or Moonlite. Blue, red and black incandescent bulbs produce low light and heat, which you can use at night. LED lights don’t produce heat, but make sure not to leave them for the whole night.

Hermit crab heating and lighting setup control

There are a few other things to keep in mind for your hermit crab setup. If using heating elements, you need to control temperatures in the tank. As mentioned above, the optimal temperature range for hermit crabs is 80-82 degrees F (26.6-27.7 C), with 75 F (23.8 C) being the lowest.

Anything above 85 F (29.4 C) is too hot for hermit crabs. Temperatures at night can drop by up 5-10 degrees (3-5 degrees Celsius), without going below 75 F (23.8 C).

Hermit Crab Heating and Lighting Requirements - Bulb Options, Temperatures
A thermostat

You need to make sure that temperatures in the tank won’t get too extreme. For this, you will need to get a thermostat like this, that comes with a probe to measure temperatures in the tank constantly. If temperatures get too high, it will turn off the heating device (on/off thermostat, but there are other types too). A thermostat is important for safety and health measure.

Another thing that will help you with light cycles and scheduling is a timer. You can connect any bulbs, fixtures, heating pads and other electrical elements to the timer, so it can turn them on and off at specified times. Unless you want a specific element to run 24/7, you need a timer to regulate day and night cycles. There are digital and manual timers that you can pick from.

Hermit Crab Heating and Lighting Ultimate Guide

Let’s also mention temperature and humidity monitoring – you will need to have a thermometer (or preferably 2 in the tank) to monitor temperatures. If you get ones with a probe, move the probe to the side so your hermit crabs don’t chew on them. Attach a thermometer/a probe around 5″ (13 cm) above the substrate. On top of that, a great tool is an infrared thermometer like this – it will quickly tell you temperatures in any spot of the tank.

Hermit Crab Heating and Lighting Guide
An infrared handheld thermometer

For humidity monitoring, you will need a hygrometer/humidity gauge. It’s best to get digital thermometers and hygrometers, and analog ones are not very accurate. If you notice that heating dries your tank too much, you can use a bubble or humidifier.

Thank you for reading this post on hermit crab lighting and heating. To learn more about hermit crab care, please see this page.