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how to take care of a hermit crab

What Do Hermit Crabs Need to Survive As Pets?

Hermit crabs have basic everyday care needs that must be met for them to thrive in captivity. That’s why you need to know how to look after hermit crabs as pets.

Hermit crabs need a glass or plastic tank, with about 5 gallons of space per pair. They live in colonies of up to 100 in the wild so they need to be around other hermit crabs to be happy.

The tank needs a substrate that hermit crabs can bury in for molting (usually sand), hiding spots (extra shells, coconut shells, pots), and things to climb for enrichment.

Hermit crabs also require two water bowls, one fresh water and one salt water (dechlorinated aquarium salt). The tank must be kept warm (80F) and humidity (80%).

What Do Pet Hermit Crabs Need in Their Cages?

If their basic needs aren’t met, hermit crabs can become sick, unhappy, or die.

You can use this hermit crab care sheet as a quick reference guide:

A glass or plastic tankIt keeps your hermit crab safe, holds heat and moisture, and ensures that all the substrate is in one place.
SubstrateTo allow the hermit crabs to burrow in order to molt and hold on to humidity/moisture.
TemperatureHermit crabs like a tropical temperature. Low temperatures will make hermit crabs stressed and ill.
MoistureHermit crabs have solid gills. They need a humid environment, or they struggle to breathe.
Thermometer and hygrometerThe temperature should be 80 degrees, and the humidity should be 80%.
Hiding spotsA half-coconut shell, broken pot, or large shell will give hermit crabs somewhere to hide when afraid.
DécorClimbing toys/plants make your hermit crabs feel more secure and provide social enrichment.
Water bowlsHermit crabs live in places where there’s standing water.

Hermit Crab Tank Setup

The tank for hermit crabs needs to be large, secure, and made of the right material. Depending on your budget, you also need to decide whether to purchase a new or second-hand tank.

How Big Should a Hermit Crab Tank Be?

When you bought your hermit crabs, you may have been given a tiny tank to keep them in. This is to give you something to take them home, but it isn’t suitable for your hermit crabs to live in as it’s far too small.

Look for a tank that’s the right size. The size of the tank depends on the number of hermit crabs that you’ll be keeping. They live in large colonies, so companionship is essential.

Approximately 5 gallons of space for 2 hermit crabs is a good rule of thumb. So, if you have 4 hermit crabs, a 10-gallon tank will be sufficient. If you have 10 hermit crabs, then a 50-gallon tank will be necessary. This will ensure that your hermit crabs don’t fight over space with one another.

What Should Hermit Crab Tanks Be Made Of?

The purpose of your hermit crab’s tank isn’t solely to keep your pets inside. It also needs to hold on to heat and humidity. So, for example, a wire cage wouldn’t work. While it’s secure, it would be challenging to keep warm and almost impossible to keep humid.

There are two materials you can consider: glass and plastic. Both are good at holding in humidity, provided that they have a solid lid in place with breathing holes.

New vs. Preowned Tank

Basic aquariums are available from just about any pet store. However, ones of the right size cost more money. So, you may want to consider getting one that’s second-hand.

There are drawbacks to buying second-hand hermit tanks, though. The tank may contain pests. Springtails, mites, fruit flies, fungus gnats, and silverfish may have infested your used hermit crab tank.

To get rid of these pests, spray the tank with a cleaning fluid or bleach solution. Leave it to soak in, and then wipe it down. Consider getting an anti-mite spray and spraying that inside. Allow the solution to dry, or the spray to clear, before using the tank.

If you do get a second-hand tank, you may need to purchase the lid separately. These are sold on a per-gallon basis. This means that the lids are made to fit the average 10-gallon tank, 20-gallon tank, and so on.

hermit crab care tips

What’s The Best Substrate for Hermit Crabs?

The substrate is another term for bedding or flooring in a cage. So, you have the bare floor of the cage, be it plastic or glass. Then, on top of that, you need to put your hermit crab’s substrate for burrowing.

Unfortunately, many of the substrates sold by pet stores aren’t suitable for hermit crabs. Pet stores with inexperienced staff may suggest aquarium gravel, which isn’t appropriate.

You can use play sand. It’s soft compared to other types of sand because the grains are small and rounded. This sand should be mixed with Eco Earth, which is soft bedding made from coconut fibers. Around 5 parts sand to 1 part Eco Earth is a good mix. You can find play sand at hardware stores.

How To Prepare Hermit Crab Bedding

Whichever substrate you use, you should sterilize it before putting it in your hermit crab’s cage. The issue with substrates is that they can contain tiny pests, usually springtails.

Line the substrate on a baking tray and bake it for two hours at 200 degrees Fahrenheit. This will kill any pests and their eggs. Alternatively, you can freeze the substrate. This achieves the same result. Freeze the bedding overnight and allow it to thaw to room temperature before using it.

Depending on the kind of substrate you buy, you can reuse it. Sand can be used indefinitely. Have half the sand in the cage, and half in the bag. Replace the sand when it’s dirty. Keep the sand you took from the cage and wash it. Then, bake it or freeze it.

How Much Substrate Does a Hermit Crab Need?

Hermit crabs need 6 inches of substrate to live comfortably. This will allow normal-sized hermit crabs to burrow, which they like to do before they molt.

However, this amount of substrate isn’t enough for each crab. Certain species are bigger than others. And according to PLoS One, some hermit crabs of the same species are bigger than others, depending on where they’re from.

A more accurate way of figuring out how much substrate your hermit crab needs is to measure its height. Your crab needs its substrate to be at least twice as deep as your crab is tall.

The more substrate that is available, the more contented your hermit crabs will be. That’s because the more substrate there is, the better it usually is for burrowing because it won’t collapse. Some species of hermit crabs prefer deeper substrate, like straws and Ecuadorian hermit crabs.

What Are The Humidity And Temperature for Hermit Crabs?

Hermit crabs require a constant warm and humid environment. While there are species worldwide, the most common pet hermit crabs are the Caribbean, Australian, and Ecuadorian species.

The precise temperature and humidity level needed depends on the species. A purple pincher hermit crab needs a lower average humidity and temperature than an Ecuadorian crab. See below:

Purple pincher (PP)75 Fahrenheit75%
Ecuadorian (E or Eccie)85 Fahrenheit85%

Hermit crabs live in different parts of the world. Purple pinchers live around the West Indies and in Florida. Ecuadorian hermit crabs are from Ecuador, which is on the equator and is hotter.

Humidity Level

If the humidity isn’t high enough, your hermit crabs will struggle to breathe properly. That’s because hermit crabs, like other marine animals, breathe through gills. When these gills get too dry, they can’t function properly.

The humidity should be kept at a level higher than 75%. Somewhere between 75% and 85% is a good range. Ecuadorian hermit crabs need a higher humidity level still.

The reason why this range is quite broad is that humidity is difficult to maintain. Keeping a constant humidity, exactly 76%, requires specialist equipment. You can keep the humidity within this range by:

  • Misting the enclosure with a spray bottle. An ineffective method.
  • Fitting a lid to the tank. Having no lid allows humidity to escape, while a mesh lid allows most to escape. A solid lid is recommended.
  • Leaving water dishes in the enclosure. Hermit crabs need water, and they give off small amounts of moisture that raises the humidity.
  • Fogger/humidifier. These give off moisture throughout the day.

All the water in the tank should be dechlorinated, whether for humidity or a water bowl. The substrate should be wet enough to hold its shape when you squeeze it, but not that it drips lots of water.

It takes a long time for this moisture to evaporate so that it can build up. This could drown your pet when it burrows to molt.

are hermit crabs easy to care for

Temperature Requirements

Temperatures below 75 degrees Fahrenheit are harmful to hermit crabs. If the temperature doesn’t go back up, your pets will become slow and sluggish.

However, temperatures that are too high aren’t good either. Higher than 85 degrees and they will overheat. They will abandon their shells if it’s too hot. It’s up to you to set up the temperature correctly. That’s because hermit crabs can’t regulate their own temperature. After all, they’re cold-blooded.

A small amount of variation is to be expected. In the daytime, the temperature can fluctuate between 80 and 83 degrees. At night, the temperature can fluctuate between 80 and 78 degrees. There’s no issue with this small temperature variance.

The temperature required varies based on species. Find out which species your hermit crab is before setting up the temperature or humidity.

Heat Requirements

There are various ways to heat a hermit crab tank. They are as follows:

  • Overhead light. Use either a regular light bulb or a ceramic heat bulb.
  • Under-tank heater (UTH). This is a mat that plugs into the mains and heats up that way.

If you get a UTH, it should be placed along the tank’s back rather than underneath the substrate. The heat mat should be from the top of the substrate to the top of the tank, and from one side to the other.

The substrate is supposed to be cool, so your hermit crabs can dig into it to cool off. It’s called an under-tank heater because it’s used that way for other pets.

If the temperature in your home is around 80 degrees already, you don’t need this equipment. But your issue then may be keeping your hermit crabs cool enough. If that’s the case, put the tank in a cool part of the home.

Thermometer and Hygrometer

To measure the temperature in the cage, you’ll need a thermometer. You want a thermometer that measures air temperature, and a digital one is recommended. Put the thermometer near or on the substrate to gauge the temperature in the most crucial part of the cage.

A hygrometer is the equivalent of a thermometer but is used to measure humidity. While you can guess the temperature in a cage, it’s more challenging to do so with humidity levels. Put the hygrometer next to your thermometer.

It’s also possible to get a combination of hygrometers and thermometers. These do the job of both, but in one digital package.

For optimal care, install one hygrometer, one thermometer, and one hygrometer and thermometer combination meter. The purpose of doing so is to ensure that all the instruments are working correctly. Hygrometers, especially, are notorious for malfunctioning. This will ensure that your pet is in the right condition at all times.

Water Bowls and Hydration

Your hermit crabs will need freshwater and saltwater in their tank. The easiest way to provide this is with a pair of water bowls. You will notice your hermit crab occasionally bathing from each bowl.

Hermit crabs must balance the salinity of the water in their shells. Too salty or too ‘fresh’ and your hermit crab will die. The water in the shell is used to hydrate the gills, which are needed for breathing.

The issue may be sand. According to the Royal Society, hermit crabs don’t like having sand in their shells. They may bathe to wash it out, so the bowls should be deep enough so that your pets can get water into their shell.

Don’t worry if the bowl has a lip. Your pets should climb it without much difficulty. But if they can’t, you may need to replace the bowl. Alternatively, put a small ramp or something similar that the hermit crabs can climb up to access the bowl. A sloping bowl is a good choice because it allows easy access and exit.

For the saltwater, use aquarium salt rather than salt from the kitchen. Use as much as is directed on the packet. The water you use must also be dechlorinated, which requires a de-chlorinator.

Décor, Toys, And Hiding Spots

Your hermit crab’s tank also needs some decorations and hiding spots to make it complete. These include the following:

Climbing Toys

Something you may not know about hermit crabs is that they love to climb. When living in the wild, they will clamber and climb over rocks during low tide. This is one way that they search for food.

You should provide climbing toys for your pets. These allow your hermit crabs to display natural behaviors in a captive environment. This is necessary to keep your hermit crab happy and contented.

You can get plastic toys, or natural toys for your pets to climb. Wood is a good choice, apart from pine, which contains phenols. Place these climbing toys directly on the substrate. They don’t need to be at an upward angle.

You could pile small branches on top of each other. This gives your pets something to sit on or climb. Aside from this, your hermit crab will benefit from other toys, not solely those for climbing, like seashells and driftwood.

If you put anything from the wild into the cage, make sure that you bake it. This includes the substrate and any wood.

hermit crabs as pets

Hiding Spots

Your hermit crabs need somewhere to hide in their tank. According to PeerJ when they feel threatened, either due to a loud noise or something moving, they may want to hide.

While your hermit crabs will have their shells, it may also seek a secure location to hide out until the ‘danger’ has passed. You need to provide this because your pets won’t have anywhere to feel safe and secure if you don’t.

Half-coconut shells are popular and stocked in most pet shops. Large, rock-like hides are too. You could also use a broken pot, or a huge shell. As long as your pets can get in and out of it, you can pick anything.

Having lots of decoration also helps your pets feel more secure. If it’s in an empty glass tank, your hermit crabs will feel vulnerable because a threat could literally come from any direction.


Live plants will make the tank more accommodating and pleasing to look at. There are many plants which you can choose from, including:

  • Bamboo. A kind of grass that grows very quickly, but unlike other grasses, it is solid.
  • Venus flytraps. Small plants with lots of stems. At the end of each is a trap that can catch flies and eat them.
  • Spider plants. A perennial flowering houseplant. It has long ‘variegated’ leaves, which means there are two colors on each leaf.
  • Pothos, or Devil’s Ivy. A pretty green ivy that can hang from the side of the tank. This is perhaps the best plant to grow in a crab tank, as it enjoys the same conditions as your pets.
  • Bromeliads. These are brightly-colored plants that grow vertically, and have densely packed leaves. Pineapples are grown on bromeliad.

You can also scatter seeds throughout the tank. Chia seeds are a choice. These will sprout, and the crabs will eat them.

Can Hermit Crabs Live Alone?

Hermit crabs are crustaceans, which are usually solitary animals. However, hermit crabs are an exception to the rule. They are clever enough to communicate with each other, so they require companionship.

A hermit crab will survive if it lives alone, and will mostly be happy. However, evidence suggests that they’re much happier in groups.

You’ll need at least two hermit crabs in the same cage. All crabs in the cage should be of the same species or they won’t be able to communicate with each other.

Hermit Crab Care Tips

Here is a quick list of things that will help:

  • Show care during handling. Don’t make loud noises or move your hand around the tank too quickly.
  • When one hermit crab is molting, separate it from the rest. The others could attack or even kill and eat it. You can use a tote or an isolation tank (iso tank) for this purpose.
  • They don’t pinch because they dislike you. They pinch because they’re hungry or because they’re afraid of falling from your hand.
  • Too much interaction is stressful. Handling it every other day should be considered the upper limit.

Hermit crabs are easy to care for in captivity once you know what they require and understand them better. They have basic care needs, are easy to feed, and can get used to occasional handling. Just be aware of the costs of hermit crab ownership.