How to Care for Pet Hermit Crabs?

Although their name suggests otherwise, hermit crabs are surprisingly sociable creatures which are super-fun to observe.

That is why they are becoming more and more popular as pets, as they do not require too much time or effort from their owners but offer so much pleasure in return.

If you are considering of becoming a proud hermit crab owner, it is necessary to do some basic research first. To ease that up, here is all you need to know on how to care for pet hermit crabs.

Hermit Crab Tank Size

The required tank size depends a lot on the size of the crab itself. If you are, for instance, planning or adopting a single smaller crab (1 inch) then a 5-gallon tank is more than adequate.

However, with just having mentioned how sociable these pets are, it is certainly preferable to house them in smaller groups. For such small crabs, a 10-gallon tank will provide enough space for a group of 3.

If you decide to start with somehow larger crabs, such as those of 2 or 3 inches, please provide them a 20-gallon tank.

That way, they will have plenty of space for exploring but also for resting in separate tank parts without having to disturb each other. And on top of that, 20-gallon tanks are much easier to setup properly.

Heating & Lighting

Hermit crabs enjoy tropical weather conditions. Their natural habitats are nearby oceans, from which they get out during their youngest phase and eventually adapt to land life.

That said, ensuring decent lightning is essential for these funny creatures to thrive. Setting up a hood bulb which doubles as a light and a heat source is therefore the ideal solution.

Be sure to choose the voltage of such bulb according to the size of the tank, or you will otherwise be faced with difficulties in maintaining the proper moisture levels.

Once lightning is installed, this will not be enough to obtain the required tropical temperature levels, so you will also be needing a heater.

Crabs are not able of creating their own body temperature, so they need to absorb this from their environment. During daytime, they will need warmer temperatures, with the ideal range being anywhere between 75-85 °F (23-29 °C).

When nighttime approaches, they prefer somehow lower temperatures, so it is best to set these around 65- and 75-degrees Fahrenheit (or 18- to 24-degrees Celsius). To obtain these, a simple under tank heater will do amazing.

Such heaters are not that much of an investment and are super-easy to install. However, place it one side of the outer tank glass, above the substrate, rather than risking burns if placing it underneath.


Choosing the right substrate type is a quite controversial topic among hermit crab owners. Some like placing sand on the tank bottom, but we find coconut fiber as a safer option.

In fact, sand can sometimes get into their shells and harden, which can ultimately bring to health complications. On the other side, coconut fiber is much softer and easier for crabs to burrow into.

The Zoo Med Eco Substrate is a greatly helpful product. It is easy to set as it simply expands when in touch with water, it absorbs odors very well and is a quite affordable option. Such substrate holds humidity perfectly, so this is surely a good option to go with.

Next, another important factor is setting an adequate substrate thickness. This depends entirely on the size of your pet crabs, but a good thumb rule for smaller crabs is a minimum thickness of 4 to 5 inches.

For somewhat larger crabs, it is best to set at least 6 inches of substrate. This is really important, as these pets tend to bury themselves while molting. Also, the thicker the substrate is the longer will it take to dry out.


Hermit crabs tend to live up to 20 years in captivity when they are provided with great care. During such lifespan, they will molt several times. Usually this happens every 18 months or so, but it can happen more often.

This is basically their natural way of growing, and it means that crabs will leave their shell and bury themselves deep into the substrate for a while. This can take up to 8 weeks for larger crabs but it is somehow shorter for smaller ones.

During molting, they are extremely vulnerable because they are growing a new exoskeleton, so it is vitally important not to interrupt them until they are done or there can be life-threatening consequences for them.

Once the molt cycle is complete, your pet crab will come out in a larger size and will be ready to house a new shell! How amazing is that?

Decoration & Shells

Providing enough shells and decoration across the tank is essential.

As they tend to grow, hermit crabs will need to house different shell sizes. That is why providing them plenty enough for them to choose from is extremely important.

Always try picking slightly larger shells from those they currently live in, but not too big or they will otherwise not house them. Shells need to be measured based on their opening side and you can simply spread them all over the tank.

Choosing the decorative items for their enclosures is just as important. Indeed, they require plenty of hiding and climbing spots, such as coconut shells or plastic houses or simple branches and driftwood.

These pets also love having plenty of plants around. The safest option (for plants) is choosing plastic ones, especially those which are a bit thicker to avoid hermits getting through them.

Live plants which are able to survive moist and warm conditions are also a great option, but be prepared to replace them regularly, as they will surely eat them out.

Food & Diet

Hermit crabs are omnivores, so they will enjoy feeding both on healthy greens and protein-enriched meals. The best way to provide them all of these nutrients in the right quantities is by offering them apposite commercial food pellets as their basic meals.

Being little scavengers, they will basically accept with pleasure every food source you provide them with, so feel free to include daily portions of fresh veggies like lettuce or carrots and non-citrus fruits like bananas or papaya.

They will also enjoy tasty meaty treats such as previously cooked chicken but also fish or brine shrimp. Additionally, you can sometimes feed them with nuts or grains, too.

These creatures are quite small so do not require several daily meals, but once before bedtime is more than enough. They are nocturnal animals so prefer feeding while you are sleeping.

Occasionally, it is necessary to spray their food with calcium supplements for a healthy exoskeleton growth, as well as cuttlebone.

Water & Humidity

In order for their gills to remain moist and healthy but also for their bodies to generally thrive, hermit crabs require high levels of humidity. Mostly, around 75- to 85%.

This can be obtained with daily misting activities, but also with foggers or automatic misting systems. Whichever solution you choose, please make sure that the levels are always inside the required parameters with the help of a hygrometer.

Additionally, these pets will need two water bowls available at all times. One should contain de-chlorinated fresh water and the other needs to be filled up with de-chlorinated saltwater.

Water is crucially important to these creatures for several reasons. Firstly, they use to drink it. Secondly, they like soaking into relaxing baths. And lastly, they need it to replenish their shell water.

Make sure to choose their water bowls wisely. They need to be approachable and deep enough for their entire bodies to soak in, but still shallow enough for them getting in and out with no trouble (they do not swim!).

Choosing Hermit Crabs

When choosing your personal mini-colony of hermit crabs, it is important to have a few things on mind.

First of all, always avoid those hermits which are either outside of their shell or have a musty smell. This often means they are molting and extremely sensitive to any stress triggers.

Taking a molting hermit out of its home and placing it into a new one may result in serious health damage and, consequentially, a premature death.

Additionally, try picking those which are in their natural shells instead of the painted ones and try counting if all of their legs are there, to again avoid choosing an already stressed pet.

And finally, please make sure to choose hermit crabs which are similar in size. This will ensure there are fewer conflicts between them, but especially for the larger ones constantly not bulling the smaller. Such behavior can often result in death, so it is best to avoid it from the beginning.

Wrapping Up

Hermit crabs are amazing, unconventional, little pets and many people around the world decide to adopt them.

If you are one of them, you have our full support! But make sure to do your research before heading to the pet store.

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

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