Home Small Pets Hermit Crab Care Guide

Hermit Crab Care Guide


Caring for hermit crabs is not always as straightforward as it may seem.  Using this hermit crab care guide, we’ll make sure you know the basics.

Before starting, I want to start with a question….What would you think if a friend couldn’t keep a puppy healthy for more than a few weeks, and replacement puppies kept dying?


Hopefully you would be alarmed. We all know dogs live for many years (on average 9 – 16 years depending on size and breed) so a drastically shortened lifespan is concerning.


But what has this to do with hermit crabs?


Unfortunately there is a great deal of misunderstanding about the care hermit crabs need to stay healthy. It is sobering to learn that whilst hermit crabs in the wild live around 30 years, their average life expectancy in captivity is just a few months.


However the good news is that with proper care a hermit crab can live a long, happy and healthy life. To make this happen, let’s first understand the basic mistakes that lead to such an unhappy outlook.


7 Ways NOT to Care for Hermit Crabs


1 – Painted Shells: Whilst painted shells may look amusing or decorative, the paint used is often toxic to hermit crabs and slowly poisons them.

2 – Solitude: A solo hermit crab is a lonely animal. Hermit crabs are actually social creatures that thrive in each other’s company, indeed they like to sleep piled up in heaps

3 – Low Humidity: Hermit crabs breathe through modified gills, and these require high humidity for oxygen exchange to work. In low humidity conditions the crabs will slowly suffocate

4 – Wrong Size Shell: Hermit crabs like to carefully select there next shell, to ensure it’s not too large or too small. When offered only one new shell in captivity the chances are its too big or too small to meet their needs

5 – Inadequate Substrate: A hermit crab needs to be able to dig and burrow. If the substrate isn’t deep enough to cover the crab entirely, this will interfere with their natural molting process

6 – Tap Water: Hermit crabs must have dechlorinated water, and it’s important to provide a supply of fresh (dechlorinated) and salt water. Also, the saltwater must be created using aquarium salt rather than table salt as the latter contains additives.

7 – A Boring Enclosure: Hermit crabs like to be busy, to climb and explore. They need accessories in their habitat that allows them to exhibit these natural behaviors, including a safe place to hide.


From this we see the traditional plastic box recommended by many as a hermit crab habitat is totally inadequate. But enough of what not to do. Let’s look at the proper way to care for a hermit crab.


Getting Started: Healthy Hermit Crab Care

Another common mistake is to think that hermit crabs are inexpensive, low maintenance pets. In some respects they have much in common with reptile-keeping thirty years ago, when lizards led pitifully short lives because they were deprived of vital UV and calcium. These days the modern reptile (and hermit crab) keeper is prepared to invest in the equipment necessary to promote health and welfare.


Basic Equipment for a Hermit Crab

Before taking on a hermit crab know that you’ll need to purchase these basics:

  • A large tank with a secure lid
  • A maximum-minimum thermometer
  • A heater or heat source for the tank
  • A hydrometer to measure relative humidity
  • A mister or means of maintaining a high humidity
  • Dishes for fresh and saltwater, plus a food bowl
  • A source of dechlorinated water and saltwater
  • Sand or coconut fiber as a substrate
  • Tank accessories such as sanitized shells, branches, stones, and hides
  • Cleaning equipment and disinfectant


Now let’s look at that crab-itat in more detail.


Tank Size

Remember how hermit crabs like company? Start by keeping two or three crabs. These require a minimum tank size of 10 gallons (enough to hold 80 pints of beer!), but once those hermit crabs are fully grown be prepared to you the ante to a 30 – 40 gallon tank.


In addition, your hermit crabs are escape artists who love to climb. This means the tank needs a well-fitting lid, preferably one with latches to prevent escapes.


75% Humidity and 75 Degrees Fahrenheit

Now to provide a good living environment. Our friends the hermit crabs’ natural home is the tropics, where it is hot and humid. Thus, you need to provide around 75% humidity and a temperature of around 75 degrees Fahrenheit.


This means providing a heat source for use on cooler days, such as a heat lamp or under tank heater. Plus, you need a means of keeping up the humidity. This could be misting the tank daily with a water spray (provided the lid is tight fitting so the humidity builds up) or providing a bubble dish (obtainable a supplier of aquarium accessories) through which air is passed to humidify it.



When it’s time to shed, your hermit crab needs to bury themselves in moist sand for 2 – 3 weeks. Enable them to do this by providing at least six inches of moist sand or coconut fiber. This shouldn’t be soaking wet, but just nicely moist. You may even want to provide higher ‘dry’ mounds so the crab can chose their perfect place to spend the day.



Hermit crabs are omnivores and in the wild will eat pretty much anything that comes their way from plankton to small shrimps. Hermit crabs are attracted to food by its smell, so seafood with a strong scent is a great way of encouraging a hermit crab to eat.


In captivity it’s important to feed a variety of foods such as fresh fruit and vegetables, plus krill or dried shrimp. Other great treats include seaweed (human grade, such as that sold to make sushi), freeze-dried plankton, brine shrimp (drained of saltwater), plant-based iguana food, and fish flakes. However, steer clear of foods that contain artificial preservatives and check the labels for sun-dried or freeze-dried methods.


Spare Shells

Give your hermit crab a choice of new condos for when it’s time to move home. Offer a range of shells so they can find the perfect fit. It goes without saying  to avoid painted shells.


Cleaning Out

Spot clean the tank a couple of times a week by scooping out soiled areas of substrate and replacing it with fresh. Two or three times a year you need to completely empty the tank of all accessories and substrate, and then scrub it out with dilute bleach to remove any buildup of bacteria. Then refresh the tank with new substrate, clean furniture and toys.


And finally, know that all your efforts will be worthwhile because a healthy hermit crab colony will give pleasure for years to come. In the same way it is not be acceptable for poor care to shorten the life of a dog or cat, neither should we let this happen to hermit crabs. So if you decide hermit crabs are the pet for you, invest in the proper equipment so they can prosper just as they do in the wild.




Basic Hermit Crab Care. Hermit Crab Association

Basic Crab Care. Hermit Crabs.com

7 Reasons why you should Never Buy a Hermit Crab. PETA

How to Create the Ideal Hermit Crab Habitat. Drs Foster and Smith