Caribbean Land Hermit Crabs as low maintenance pets


Many pet stores sell crabs claiming that they are a low cost and low maintenance pet.  My experience has been that those two claims are contradictory.  By investing the right equipment I have created a low maintenance environment for my Caribbean land hermit crabs.  I have not lost, or added, a hermit crab in over 3 years.  They successfully molt in the tank as well. The cost was somewhere between 100 and 200 dollars.

Disclaimer:  This has worked for me but I cannot guarantee that it will work for anyone else.  I kept crabs for 2 years in the conventional manner before I achieved this balance.  You can see the evolution of my crabitats.





Tank (20L or larger)

I recommend fish tanks over reptile tanks as they are constructed with a heavier glass.  I once cracked a reptile tank leaning on it to get to the far corner.  I have never had this happen with a fish tank.  Glass is better than plastic because the sand will scratch the surface of the plastic.  A 20L (20 gallon long) tank is 2' long and high.  my experience is that smaller tanks quickly become crammed full of crabs and decorations.

Top for Tank.  (If using a screen a heavy vinyl cover is also required)

The top of the tank serves 2 purposes, to keep the crabs and humidity in the tank.  While a screen top will do the first, it does nothing for humidity.  My tank has a screen top and I keep it covered with part of an old shower curtain.  When the ambient humidity is low I put weights on top of the plastic to seal the tank better.  To reduce humidity I lay the plastic on more loosely.

Humidity Gage

An accurate humidity gage is a must.  It needs to be placed where it is easily seen.  Ideally it should not be next to your humidity device.

Humidity Control Device

Hermit crabs have modified gills and breathe best when the  relative humidity is between 60% and 80%.  By keeping the humidity within that range I have eliminated the need for bathing and misting my hermit crabs.  There are several devices on the market for producing humidity in an enclosure.  You are most likely to find them in the reptile section of the pet store or catalog.   I use a Tropic Air humidifier and air exchanger.  You can find it sold with the air pump as well as without.  The reservoir is external to the tank and usually lasts a month for me.  I have had problems with the connector for the air tube to the humidifier, but was able to replace it with standard fish tank tubing parts.

2 Temperature Gages

Place one temperature gage near the substrate and the other near the top of the tank.

Temperature Control Device

The minimum temperature is 65 and the maximum is 85.  I find that my crabs are most active when the temperature is over 75.  Most people use a UTH (under the tank heater) for their crabs.   These are plastic heating pads that permanently adhere to the bottom of the tank.  I have seen recommendations that some sort of barrier be used to keep the crab from burrowing to the glass right over the UTH.   Depending on your substrate thickness the UTH may only heat the sand and have little effect on the air at the top of the tank.  Reptile heat bulbs can be used to rectify this, but as they are usually designed for higher tank temperatures great care must be taken in monitoring them.

I know of no device to cool a tank so it is imperative that the ambient room temperature be less than 85.  

Sand Substrate

The substrate must be deep enough for you largest crab to bury himself in.  Multi depth substrate can be created with barriers so that a deep section is available but the rest is more shallow.  Look in the fish section of your pet store or catalog for products designed for this function.  I use play sand but there are some that have issues with a silica based sand.  Other options are to find a calcium based sand for small gravel.  I do not recommend the coconut husk beddings as I have found that they mold easily.  My goal is to not have to change the substrate more than once a month and I plan the material and number of crabs accordingly.

Water Bottle

A water dish with an attached reservoir cuts down on the frequency that fresh water needs to be provided.  I use a Repti Rock Reservoir because it provides steps to allow small crabs to exit the bowl

Food Dish

Even though the crabs are likely to drag some food out of the dish, and sand into it, a food dish is a good idea because it allows you to more easily remove the rest of the leftovers.  The food dish should be shallow enough that your smallest crab can climb in.  Look for food dishes in the reptile section of your pet store or catalog.  Many even carry dishes explicitly designed for hermit crabs.  Another choice is to use a flat shell.  Always place fresh/wet food  in a different dish than dry food.

Climbing  and Hiding places

Be creative.  There are the standard coconut hermie huts, but don't be limited to that.  Look in the fish section of your pet store or catalog and see what kind of polyresin ornaments you can find with large cavities and rough surfaces. (mine love to climb on and hide in their Aquatic Gardens Wet N' Wild 4-Faced Buddha Ruins Aquarium Ornament.)  I have also had crabs that liked to hide in silk plants, especially if they are attached to a piece of wood.  With some slate and aquarium silicone you can make a cave, perhaps even a shelf on top that will give the tank another level.   My crabs love to climb on a piece of wood I have which has a lot of recesses on it.  I found the wood in the aquarium section, but there is wood available in the reptile area as well.    Do not use wood collected from outside as it can contain insects and may even be toxic to your crabs.  

Extra shells

Painted shells can be used to make interesting decorations, but given a choice the crabs will select something else.  It is better to offer natural, polished, or even carved shells.  Be sure all shells are clean and rough edges around the opening have been smoothed.  Rotate the shells periodically.  The crabs love exploring and trying on new shells but find old ones boring.  I once placed a large shell in and in the morning found a small shell in it's place.  Apparently that one shell had allowed 6 crabs to get new shells.

Non-stressed Caribbean Land Hermit Crabs

All Caribbean land hermit crabs have been harvested from the wild.  The rough handling, forced shell changing (if they now have a painted shell) and poor store conditions take a great toll on them.  Never buy a crab that is missing a limb or is lethargic since these are signs of stress and could be accompanied by imminent death.  Crabs are not considered non-stressed until at least 2 months after you buy them.  It is then your responsibility to provide as stress free environment as possible.

The number of crabs you can keep in a tank depends on the size of the crabs and size of the tank.  Hermit Crabs are social animals, but they do need to be able to go off alone if they like and especially be able to get away from the other crabs to molt.

Second Water Dish for Brackish Water

Caribbean land hermit crabs spend most of their lives away from the sea and only require fresh water.  Many people do feel that it is a good idea to provide them with the option of drinking or bathing in brackish water.  Since the water we give them is treated or, as in my case distilled, they might find some mineral benefit from the brackish water.  To create brackish water buy an aquarium salt water mix from the fish department of your pet store or catalog and mix it up at half strength.  The brackish dish can be filled occasionally or constantly depending on whether or not you find that your hermit crabs like it.  IMPORTANT:  Brackish water is not a replacement for fresh water.  Fresh water must be available to your hermit crabs at all times

Large Bathing Pool

Since we are no longer actively bathing our hermit crabs, offering the option of passive bathing is an option.  Passive bathing means that the crabs can immerse themselves in water if and when they choose to.  In the reptile section of your pet store or catalog you can find dishes with small steps that a crab can crawl entirely into.  The stairs are to keep smaller crabs from getting trapped.




    Feed Crabs - remove old food and replace with new

    Check water - add when needed

    Check Humidity - adjust as needed

    Visually Check crabs to be sure they are healthy

    Observe sand for problems like mold or gnats.  Presence of either will mean a sand change is required.


    Replace sand.

    Check crabs to be sure they are healthy.


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