Hermit Crabs – Detailed Guide: Care, Diet, and Breeding

Hermit crab guide

Hermit crabs can make very rewarding pets when kept properly. We often see them, with decorated shells in small plastic tanks in pet stores. However, land Hermit crabs require a bit more care than you may have been led to believe.

These interesting little creatures actually have very specific needs and often times they aren’t cared for properly. This guide will help you to avoid mistakes so your Hermit crabs can thrive in their crabitats.    

Of course, there are many different species of Hermit crabs and some of them require a different approach. Nonetheless, even though some species are more sensitive than others there are still some basic rules to follow for all of them.

Quick Notes about Hermit crabs

Name Hermit crab
Other Names
Land Hermit crab
Scientific Name Coenobita sp.
Tank size (minimal) 10 gallons (~45 liters)
Keeping Easy-Medium
Breeding Very Difficult 
Size 1.5 – 15 cm (~0.5 – 6 inches) depends on the species
Optimal Temperature 26 – 30°C  (~80°F – 85°F)
Water type Freshwater and saltwater bowls
Moisture at least 75%
Substrate At least three times deeper than the crab
Diet Detritivore /omnivore
Temperament Pieceful. Social  
Life span up to 30 years and more
Color Form Purple, orange, yellow, red, etc

Natural Habitat of Hermit Crabs

Hermit crabs are native to the Indo-Pacific region, the Western Caribbean and the Western Atlantic, where they can be found along the beaches, near the water. Although they are born in the ocean they spend the rest of their lives on beaches or further inland. 

Species Description of Hermit Crabs

Unlike most crabs, Hermit crabs do not have an entirely solid exoskeleton and their abdomens are soft (uncalcified) and vulnerable. Therefore, it is absolutely crucial for them to wear shells. The shell provides protection and a place to hide.

Once they find one that fits, they tuck themselves into it and carry it with them everywhere, until they eventually outgrow it.

Hermit crab and strange shellsNote: Obviously it is not possible to identify Hermit crabs by their shells. These shells can be any size or any shape. If the Hermit crab can fit, he’ll use it. For example, in the wild, people found Hermit crabs wearing even plastic bottle tops.

Hermit crabs come in many different colors. These colors can be helpful in determining which species of Hermit crab you have.

  • Claw Color

With most Hermit crabs, the crab’s claws will be the same color as the rest of his body. The Caribbean hermit crab is the exception to this rule. Caribbean hermit crabs have pincers that are bluish-purple in color, giving them the name “Purple pincher”.

  • Body and Leg Color

Body and leg colors vary between species. Caribbean hermits have vivid orange to red-colored legs.

In contrast, the Ecuadorian hermit crab is a green to blue color. Ecuadorian crabs can change colors as they age, with the oldest of adults taking on a tan, or orange color to their body, while retaining their green legs.

Long-clawed hermit crabs have tan bodies that are tinted red and broad-claw hermit crabs come in gray, tan and a light red, or rusty color.

  • Adult Size, Age

The adult size of your Hermit crab depends on quite a few factors. These factors are age, species and shell size. Unlike some kinds of crabs, Hermit crabs never stop molting, as such, they never stop growing. Because of this, the largest Hermit crabs are the oldest.

Species plays a big role in how big your hermit crab is capable of getting throughout its life. Some species grow rapidly, while others are slow and steady.

Caribbean Hermit Crab – Scientifically known as Coenobita clypeatus, this crab grow to be larger than a baseball or softball. This species can reach sizes of up to 6 inches in diameter.

Ecuadorian Hermit Crab – Also known as Coenobita compressus, this hermit crab is one of the smallest. They barely reach an inch in diameter, even at a ripe old age.

Strawberry Hermit Crab – Coenobita perlatus is known as the strawberry crab, due to its red coloring and strawberry-like body shape. These crabs reach up to 6 inches in diameter.

Ruggie Hermit Crab – The Ruggie crab, Coenobita rugosus is another fairly small hermit crab. Throughout their lifetime, they only reach a size of about 2.5 inches in diameter.

Coconut Hermit Crab – These crabs, also known as “Birgus latro” aren’t the kinds of hermit crabs you want for a pet. You won’t find them in any pet store, however, if you’re exceptionally brave, you may find an equally brave, private dealer that has them. These crabs reach sizes of 40 inches from leg tip to leg tip and weigh up to 11 pounds. They have claws that are big and strong enough to crack open coconuts! They are known, not only for their sheer size but also for their mean temperaments.

Determining Gender of Hermit crabs      

Female hermit crabs have gonoporesHermit crabs are one of the few kinds of crabs that are only able to be sexed by viewing their genitalia. To do this, you will have to “convince” your crab to come quite far out of its shell. Most hermit crab keepers sex their crabs during a shell changing period, however, it is important to be exceptionally gentle with a shell-less hermit crab.

Important: Never try to force, or pull a crab out of its shell. The crab will fight until the end and can be severely injured before allowing you to pull it out by force.

Female hermit crabs have tiny genital openings called gonopores. These openings can be located on the first segment of their back legs. They are located close to the body around the cephalothorax and abdomen joint.

These openings are where a male hermit crab injects his spermatophore during the mating process. Males will not have these openings. The gonopores of female hermit crabs are situated in about the same place, regardless of species.      

Hermit crabs Lifespan

Land Hermit crabs can live from 2 to 30+ years.

In the wild, most species of Hermit crabs can live to around 30 years old. Some species even live to see their 70th birthday. In captivity, many Hermit crabs are lucky to see their second birthday. This severely shortened lifespan is often due to improper care and uneducated hermit crab keepers.

If you provide your Hermit crab with the best care possible and meet all of his needs, you could have your pet for a very long time.

Keeping Hermit Crabs    

Contrary to popular belief, it is not easy to keep a Hermit crab healthy or provide it with what it truly needs to thrive. There is a big difference between thriving and surviving after all.

If you want to have a happy and healthy Hermit crab, for more than a few months it is important to give it everything it needs, including proper care. In other words, ditch what the pet store told you about how easy of a pet they are.

  • Tank Size

If you Hermit crab is young (2 years and less) and still small (2.5 cm or 1 inch), it is theoretically possible to use 5-gallon tank. Keep in mind that they require 2 water dishes (freshwater and saltwater) that are deep enough for them to submerge themselves in.

In addition, you need to provide them with climbing and hiding places. Hermit crabs will also need some open space to run around and do their “Exercises”.

As you can see, it is almost impossible to fit all this in a 5-gallon tank. Therefore, I would say that the recommended minimum size is a 10-gallon tank.

Note: If you are planning to keep Hermit crabs it will be better to have a bigger tank right from the beginning. Although, adult Hermit crabs do not grow too fast, the smaller they are, the faster they will grow. Therefore, eventually, they will need a larger tank in any case.

  • Exercise

Yes, Hermit crabs need exercise too. For the most part, they will get plenty of it all on their own. That is, if you provide them the means to play.

Hermit crabs love to climb, pull, crawl and rearrange their substrate. You should provide your Hermit crab with plenty of things to explore, climb on and hide in. If you’re careful, you can even walk your Hermit crab across your hands.

  • Humidity

You may be familiar with the clear plastic critter carriers in which pet stores house and display their Hermit crabs. These are not suitable homes for Hermit crabs and they can even be considered cruel. The ventilation tops are a slow, painful killer for a Hermit crab.

Hermit crabs do not have lungs and they cannot breathe in water or dry air. They breathe through modified gills. This leaves the Hermit crabs in a precarious situation where they are constantly dependent on moist, humid air to breathe. Humidity level for Hermit crabs should be at least 75%.

If the gills dry out, they will die a very slow death caused by suffocation. It can take months for the crabs to succumb to it. This means that humidity levels are literally a life or death situation for a Hermit crab and an overly ventilated top, in a heated enclosure is a death sentence.

Note: You need a lid. First of all, make sure your tank is covered, with a lid to keep the humidity in. Second, keep in mind that Hermit crabs are escape artists.

  • Heater

Hermit crabs prefer worm temperature 26 – 30C (80 – 85F). Some species, for example, Caribbean Hermit Crab can tolerate slightly lower temperatures down to 23C (~75F).

However, be very careful here! For example, a heat lamp can dry out your tank. If you use an under the tank heater, it can overheat your substrate and burn or kill molting crabs there (Hermit crabs bury to molt).

The best (safest) option will be to put the heater to the side of the tank.

Tip: If you have a 10-gallon tank, choose one, which is rated for at least 20 gallons. The difference in money is minimal but the benefit is huge!

  • Bathing

Yep, your hermit crab might need a bath. In general, Hermit crabs kept in properly humid enclosures don’t need to be bathed and bathing them can actually do more harm than good. However, there are two instances when it is important to bathe a Hermit crab.

1. You Have a New Hermit Crab

If you’ve just bought a new Hermit crab, it is important to bathe him, or her before moving them in with your other Hermit crabs. This ensures there are no lingering scents from the pet store or previous residence that will lead to problems (even conflicts with other Hermit crabs). Hermit crabs that all smell the same are happy Hermit crabs

2. Your Hermit Crab Just Finished Molting

A freshly molted Hermit crab should be given a very gentle and very quick bath after emerging from his molting hideout. Freshly molted hermit crabs smell like shed exoskeleton, which is expected. But, to your other Hermit crabs, this smell is similar to an all you can eat buffet. To prevent cannibalism, be sure to bathe all the newly molted crabs, before placing them back into your colony.

Note: Hermit crabs do not need soap to take a bath, just a shallow container filled with de-chlorinated room temperature water, not hot, or cold. On occasion, you can add a few drops of stress coat, or other hermit crab bath product to the bath for a special touch

  • Substrate

Sand or Coconut Fiber Substrate is the best options for Hermit crabs. The substrate itself must always be moist.

Warning: Do not use calcium sand. It can harm and kill Hermit crabs.

Important: Hermit crabs are burrowers. Therefore, they need at least 7 – 10 cm (3 – 4 inches) of the substrate. It should be at least three times deeper than the crab.

  • Shells

It is very important to always have extra shells in your tank. Most Hermit crab keepers will say that 3 – 5 shells are the minimum. However, you cannot give them any shell you like.

  1. Sea snail shells are the best choice.
  2. The aperture should be wide.
  3. The shell should not be painted.
  4. Boil the shells in saltwater to make them more appealing to the crabs.

Hermit crabs “investigate” empty shells by examining the shell exterior using their antennae and claws by inserting them into the shell aperture. “Shell switching” takes place when the crab holds the new shell with the aperture facing upward and releasing its abdominal grip on the old shell, rapidly swings its abdomen over to occupy the new shell. Solitary crabs often retain hold of their original shell and “reversals” occur when a crab moves back and forth between shells before finally choosing one.

Tip: Often Hermit crabs can bury shells they do not like. To prevent it, you can put all shells in a basket. They will pick one they like the most without scattering them around.

  • Water Requirements    

Hermit crabs are not aquatic and some species are even hydrophobic. However, all Hermit crabs regardless of species should have a suitably sized bowl of water available to them 24/7. The water bowl should be big enough for the Hermit crab to fully enter it.

As I have just said earlier, you need to put 2 water dishes (freshwater and saltwater). When you prepare saltwater use only products for marine fish.

Note: It should be easy for the crab to crawl in and out of the water source. They can drown.

It is important to provide your Hermit crab with chlorine and fluoride-free water, as these things are toxic to them. A general rule of thumb is if you would not put a sensitive tropical fish in it, do not give it to your Hermit crab.

Use a water conditioner for their water. For example, Searchem Prime will remove also toxic gases, bind to heavy metals, any ammonia, nitrites or nitrates present for up to 48 hours.

Another option is to give them bottled spring water or at least age tap water for them.

Tank Equipment (examples with links to check the price on Amazon)

Read my article “Hermit Crab Tank Setup”. 

Feeding Your Hermit Crab    

Hermit crabs are omnivores and scavengers. Some people prefer to feed just commercial crab food in the form of pellets, which contain most of what your crab needs. Though, your Hermit crab will appreciate the occasional fruits, or vegetables to supplement his diet and give him some variety.

Even Hermit crabs appreciate something new to try once in a while. Look into home-made food options too. According to the study, captive Hermit crabs express food preference, but only on an individual level.

Note: Without a very or proper diet, they can even seek out other hermit crabs and cannibalize them.

Therefore, fresh or dried fruits and veggies, some kind of protein meaty product, eggs, etc. should be on their menu. It is also good to give them some cuttlebone for calcium. 

Read more about it in my article “Hermit Crab Diet”.

Hermit Crabs and Tankmates    

First things first, Hermit crabs do not like to live alone. Despite their name, they are definitely not hermit-like in any way. They are actually very social creatures, who will readily interact with one another and throw crab parties in their enclosure all night long.

In the wild hermit crabs move along the beach in groups of 30 or more crabs and are seldom seen alone. Ideally, you should never keep a hermit crab alone. If you have one, you should buy him a friend, or two, or three.

Tip: When you pick out Hermit crabs in the store, try to pick crabs of different sizes. The point is that they will compete and even fight over shells. Hermit crabs with the difference in size are more likely to get along better.

Due to their specific needs, shallow water, and dry land requirements there aren’t many other invertebrates and surely not any fish that could happily live with a Hermit crab. The general answer to the question of tank mates for Hermit crabs is – get more Hermit crabs.

Some hobbyists have reported successfully keeping hermit crabs with other crab species, but I don’t recommend this. It is almost never a good idea to house more than one kind of crab together.

If you absolutely want to liven up your crabitat, you could consider planting it. Various kinds of plants will happily grow inside a hermit crab enclosure and while they aren’t creatures, they are living things that grow and change.

Breeding Hermit Crabs    

It is never easy to successfully breed any kind of crab in captivity, and Hermit crabs are not an exception. That is why almost any crab that you see in a pet store has been removed from its home in the wild.

Nonetheless, if you are still interested in breeding them, you need to know several things. The breeding cycle of Caribbean Hermit crab was studied the most. Therefore, I will talk about them.

After mating, it takes eggs approximately 1 month to hatch. You will see it when the eggs change color. For example, although all adult Caribbean Hermit crabs are fully terrestrial, their larvae develop in the plankton (larvae or zoea). Once they are a dark gray, if you are successful, you will see tiny zoea hatching from the eggs in the water.

At that moment you need to transition larvae into a separate tank. Even a small one like 5 – 10 liters (1 – 2 gallons) will be good enough. If you do not do that, adults can eat tiny larvae.

The larvae need saltwater with optimal temperature 26°C or 78F. The ratio should be 1 teaspoon of salt to every cup of water. The water should have a pump that sprays or moves the water in a way that simulates gentle waves. Do water changes to prevent ammonia.

Tip: To avoid larvae from being sucked in during water changes, use a trick with the light. Light attracts Hermit crab larvae. So, lure them to a spot with a flashlight or adjustable spot desk lamp to the corner of the tank. Then do your water change.

Hermit Crab Larvae Stages and Feeding

Hermit Crab Larvae Stages According to the study, Hermit crab larvae usually pass through five larvae stages before metamorphosing into Megalopae (final stage of transformation). Each larvae stage last about 5 – 6 days. While Megalopae stage lasts around 30 days. During this period, the larvae grow up to nearly 4 – 6 mm.

At the final stage, baby Hermit crabs become more benthically oriented, show an escalating interest in shells. They emerge onto land where they burrow and molt to the first juvenile crab stage.

Note: The survival rate is pretty low. In experiments, only 12% of the larvae survived to the final stage and even less the finals stage itself.

For the first two weeks feed the baby Hermit crabs a solution of marine infusoria, powdered spirulina, newly hatched brine shrimp (Artemia) once a day. Then they can eat larger 1 – 2 day-old Artemia. You should also supplement their diets with thawed zoo-plankton food at least once every other day.

After two weeks, provide the babies will tiny cone-shaped shells and a fine grain sand bridge to exit the water. The tiny hermit crabs will begin to exit the water. Once the crabs have ventured onto land, you should provide them with shallow bowls of freshwater.

After 40 days, the baby crabs can be placed in a regular hermit crab enclosure.

Conclusion

The recipe for healthy Hermit crabs is simple. Keep your Hermit crabs warm with 4 – 6 inches of moist substrate. Give them access to freshwater and saltwater bath. Add some friends. Do not forget about moisture and change their diet from time to time.

Although the initial setup for the Hermit crab can be pretty costly, it will pay off in the end. First of all, after that, there is almost nothing you need to do to the tank unless something goes wrong. Second, they can make you a company for many years. Third, Hermit crabs are a lot more fascinating than people tend to think.

Related Posts:

Hermit Crab Tank Setup 
Hermit Crab Diet
Everything About Hermit Crab Molting
Hermit Crab Shells: What You Need to Know

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