BASIC CRAB CARE
Chances are, if you're visiting this site, you are the happy
owner of at least one land hermit crab. Congratulations on your unique
and exotic pet! This site will help you provide your little friend with
the very best environment possible while in your care.
To live comfortably in captivity, hermit crabs require the following:
Temperature no lower than 75°F. Consistent low temperatures can
kill a hermit crab. Don't allow them to bake in a window, either. If
they get too hot they will die, overheating causes irreversible
damage and a slow, painful death. Signs of overheating are a musty
smell and discharge of brown liquid;
A constant humidity level of at LEAST 70% humidity. Try to remember
that you want the inside of your crabitat to have a moist, "tropical"
feel to it;
Substrate deep enough that the crabs can bury but not so deep that
it negates the effects of your under-tank heater. If you are having
trouble keeping your crabitat warm, try moving some substrate from over
the heater. If you are having trouble getting the crabitat to cool
down, turn off the heater. See the molting
page if you need information on heating a molter's isolation tank;
Food, water, shells
and other tank decorations to keep the crabs engaged and active.
I'm sure you've heard this before, but you really shouldn't keep only
one hermit crab alone as a pet. The name 'hermit' is misapplied to our
little friends -- they are quite gregarious and like to be around their
own kind. In the wild, they travel in packs of up to 100 crabs,
scavenging the beach for food and shells. The reason they travel in
packs is simple: Where there are more crabs, there are more shells.
Researchers have found by putting one clean, empty shell on the beach,
they can initiate a "cascade" of shells changes: One crab changes in to
the new shell, another changes into his old shell, and another changes
into the other empty shell, and so on. Quite often I find about 20
hermies of my clan all piled on top each other, sleeping. So, please
don't consign your friendly hermie to a life of loneliness. As one
seasoned crabber once remarked, "Two crabs does not a colony make." Go
get him a friend, or better yet, two friends.
The very first thing your new pets will need is a 'crabitat.' A
is where your hermit crabs will spend most of their time, so choose a
that is clean and roomy. A 10-gallon glass aquarium can be purchased at
a reasonable price and makes an ideal 'starter home' for your crabs. If
you are unable to purchase an aquarium, there are other options
available, such as plastic critter carriers. Keep in mind how many
crabs you ultimately plan on housing and how you would like their home
to look. It will help you make up your mind when the time comes to
decide on the size of your crabitat. Make sure the cage will hold your
pets, their food and water dishes, extra shells and climbing toys. You
want a cage large enough to hold all these things and still have space
for the crabs to roam if they wish. This means that the small
plastic box that you got from a mall kiosk or boardwalk store is not an
adequate shelter for any hermit crab. One way to give the crabs
room to wander is to leave an area at the back or front of the crabitat
that is completely clear of obstructions. This way the crab has an
"express lane" to run down if s/he needs to get some energy out and
doesn't want to climb. While a plastic critter carrier makes a passable
temporary home or
'hospital cage,' it is not recommended as a permanent home.
most important aspect of the crabitat is the type of
substrate you put on the bottom. After all, your crab
will in all likelihood be sitting on it every day! There are many
different types of substrate available, but not all of them are ideal
for land hermit crabs. You want a substrate that is relatively easy to
clean, attractive and holds up to hermit crabs' tunneling activities.
The best substrates are sand and coconut fiber (also known as Forest
Bedding®, Bed-A-Beast®, and Eco-Earth®.
Sand. There are
also many different
varieties of sand available. The most
expensive ones come in small bags and are labeled as special "hermit
crab sand." Don't be fooled! When it comes to general crab care, "sand
is sand is sand" and it doesn't matter where it comes from, as long as
it is clean. You can get a 50 lb. bag of clean play sand from a
hardware store for the same amount you'd pay for 2 small bags of
"hermit crab sand." (Try to get a bag of play sand which is towards the
middle of the pallet, otherwise, it may be wet or contaminated.) A word
of caution about play sand. Some crab owners have reported problems
with an orange-colored play sand they purchased from Home Depot. The
sand had an oily, diesel-like smell to it. If you open the bag of sand
and notice any "off" smell, throw it out or take it back to the store.
Do not put any strong-smelling sand into your crabitat. One sand that
has been of consistent good quality is "high desert sand." You only
need to concern yourself with special sand if you have a sick crab that
needs calcium. Most sand comes pre-washed and/or sterilized. Sometimes,
individual bags can develop leaks through which moisture, insects, etc.
invade. As a precautionary measure, please take a close look at the
substrate before you put it into your crabitat. Pour some into a bowl
and sift it through your fingers, hold it to a strong light and watch
for insects. Lastly, put your nose to it and take a whiff to check for
a musty smell which would indicate moisture contamination.
fiber (Forest Bedding "FB" or Eco-Earth) is another excellent
The coconut is processed to be very fine, almost like earth, and
pressed into a dry, hard brick. To prepare FB, you put the brick in a
large bowl or tub and add enough water until the brick absorbs the
water and become soft enough for you to break apart with your hands.
Then you add the moist FB to your crabitat. There are many benefits to
using forest bedding, not the least of which is that it appears to be
one of the very best molting mediums out there. Over time, the FB
compacts a little bit and becomes stable, which allows the crabs to dig
little tunnels all through it. An advantage of the FB over sand is that
FB will not collapse heavily upon a newly-molted crab and damage it. I
have had many beautiful molts in the FB. The moisture in the FB helps
to keep the humidity in the crabitat at a good range, without resorting
to sponges and misting. FB prepared as directed above is adequate, but
if you want to make it
extra special and healthy, you can prepare it using pre-prepared salt
water instead of regular water. First you mix up your salt water
according to the package direction, and then use the salt water to soak
your FB. Hermit crabs love to eat FB and this helps them to get other,
needed minerals in their diet. There is one unique drawback to using FB
and that is that it attracts
fungus gnats. Fungus gnats are teeny black bugs that look like midget
mosquitoes. They are attracted to warm, moist areas and will lay eggs
and start a colony of their own in your crabitat. Fungus gnat larvae
are worm-like with black shiny heads.
Since hermit crabs and fungus gnats are both arthropods, you can
not use any pesticides in your crabitat or it will kill the crabs!
There is however a solution to this problem. Back in October 2003 I
found and used -- biological warfare! You can view all the
creepy details on the FAQ page. Some people who
have mixed their FB with saltwater have reported fewer fungus gnats.
is the latest and probably the best idea. It is a
combination of coconut fiber and sand. You prepare the coconut fiber as
you would normally, and put it in the crabitat. Then you add sand and
mix it all together well until it is a nice, diggable consistency.
Generally you want your substrate to be the same consistency as the
sand you'd use to make a sand castle. Not too dry and not too drippy.
There is one universal problem with all good hermit crab substrates.
They are messy. Expect to have sand or forest bedding in your kitchen
and bathroom at one time or another. Hermit crabs are not the most
orderly critters and they do drag sand, FB or what have you into their
food and water dishes. Also they bury shells that they aren't
interested in. So you'll be cleaning out their dishes and shaking
substrate out of shells, no matter what substrate you use! If it's
crab-friendly, chances are it's going to be messy.
WATER: DRINKING AND
basic rule of thumb for land
hermit crabs’ drinking water is this: Do not give the crab any water
you would not put in a tropical fish tank.
This means that you’ll need to remove the chlorine and other harmful
chemicals from water prior to giving it to your crab. Bottled and
filtered water are also acceptable, but usually more expensive. Plus
there is no way of guaranteeing that during processing (with bottled
water) that the chlorine was adequately removed or (with filtered
water) that the filter you’re using wasn’t clogged or contaminated. I’d
go with the method below, regardless of the type of water you use.
Removing the Bad Stuff:
Chlorine is harmful to land hermit crabs. Repeated exposure to it
causes blisters to form on the crabs' gills, resulting in suffocation
and death. You can remove this harmful chemical by purchasing from your
pet store a general dechlorinator (or tap water conditioner). It’s
relatively inexpensive and usually comes in a dropper-style bottle. You
do not need to buy a large amount of it (in fact, you shouldn't,
because the drops may gradually lose the ability to dechlorinate the
water if stored for a long period of time). Try to get a brand with
instructions on how to mix only ONE GALLON of dechlorinated water,
otherwise you’ll have to do some calculating as to how many drops per
quart, etc. Read the
instructions on the
bottle or packaging. Usually you'll need something like 1 drop per
gallon (if the dechlorinator is really
strong) or 5 drops per quart.
Check your individual brand, though, because the amount per brand can
vary significantly. Put the required amount of drops in the bottom of
the gallon (or ˝ gallon) jug and fill it up in the sink, tub, whatever.
I usually let the water sit open overnight after treatment, to be sure
all the chemicals are neutralized.
Once you've dechlorinated the
water, it can be served to the crabs in practically any non-metallic,
non-porous container. The two things you need to consider when
selecting water dishes for your crabs are: How much water it will hold;
and how deep the container is. If you have large crabs, you will need a
larger container, obviously. Hermit crabs like to drag themselves
(shell and all) into the water dish and just sit there sometimes. They
may be replenishing their ‘shell water’ or they may be cleaning out
their shells. It’s important you check the water dish daily, and make
sure that it is clean and full of water. To clean the water dish, run
it under the tap and dry it well with a dishcloth. The best water
dishes I have seen are molded plastic or cement reptile-type dishes
that look like rock, sea shells, plastic jar lids and
individual-serving size small Pyrex casserole dishes. NEVER use
anything metal as a water dish. Land hermit crabs are extremely
sensitive to metal.
IMPORTANT! Be sure
your water dish is not so deep that your smaller crabs will drown in
it. If you have large crabs and small crabs together, put pebbles into
the large crabs’ dish so a stray small crab will
have a way to get out if it stumbles into the large dish. Smaller water
dishes and jar lids don’t need a sponge in them, but a sponge is
critical if you’re using a large clam shell, which may be very deep
toward the middle-back areas. If the water seems deeper than your
smallest crabs, don’t take the risk. Put a sponge into the dish.
Wash Yer Dishes!
You may notice when you refill the crabs' water dishes that there is
sometimes a slimy residue in the bottom of the water dishes. This
‘scum’ is probably the residue from the (traces of) oil that is used in
many commercial crab foods. This oil is used since our hermies
need a bit of it in their diet. However, this does NOT mean to add
extra oil to their crab food or feed them extra oil -- THAT could kill
them! Another culprit could well be the oils from
the natural foods (such as the coconut, etc.) you feed your crabs. The
scum is probably a residue of this oil, combined with food particles
and other items the crabs drag into the dish along with them. It is no
cause for alarm. Just scrub out the scum (do NOT use any chemicals, a
damp paper towel works perfectly).
To bathe or not to bathe?
There is a lot of debate among hermit crab lovers as to whether bathing
land hermit crabs is in fact necessary. When I was growing up it was
taken as gospel and was held that way until maybe three years ago at
The arguments for and against
bathing can both be made to sound very good. Over the years what
I have owned hermit crabs, however, I have come to stop bathing them
completely. At first this
was because I took into my care several species of exotic hermit crabs
and I was unsure about their care. As time went by and all my crabs
benefited from not being bathed, I decided to abandon the practice. Now
my crabs receive a bath only after coming up from a molt, before being
introduced to the rest, or in special circumstances.
The general rule for bathing is
thus: If you keep the humidity level of the crabitat at the desired
level (above 70% relative) then bathing is actually
stressful to the crabs. This
is not to say that hermit
crabs should never be bathed. What they need is to be able to bathe
themselves when they feel the need. You should provide them with
dishes of dechlorinated water (both
fresh water and salt water) deep
enough that the water will flow into the crabs' shell when the crab
climbs into the dish. That is approximately one full inch of depth for
large crabs, and a half-inch or less for smaller hermies. IMPORTANT:
ALWAYS PROVIDE A WAY FOR THE HERMIT CRABS TO CLIMB OUT OF THE POOL!
Add a snip of sponge, a shell or pebbles, but always, ALWAYS have
something in the pool they can cling to if they are uneasy with being
in the water or especially if smaller crabs tumble in by accident.
Some species of hermit crabs
are terrified of exposure to water. The Indonesian species Coenobita
brevimanus in particular is very sensitive to any water exposure.
You can read up on it here.
After an initial very gentle bath, in which the crab is very slowly and
gently immersed in the water and quickly removed, the crab should not
be bathed AT ALL. In fact, if you isolate these crabs from the rest of
your crabitat for a month and do not notice any sickness, you can
probably skip bathing them altogether. Regardless, ALL hermit crabs
MUST have the opportunity to enter water if necessary. The species Coenobita
perlatus or "strawberry hermit crab" in particular suffers and dies
a slow painful death if deprived of salt water. All hermit crabs
require salt water to regulate the saline content of their bodies.
Bathing new crabs
Hermit crabs that you just purchase from a pet store should be bathed,
if to only get the grime off them and make them "smell the same" to the
other hermit crabs. New
molters should also receive a
quick and gentle bath once they have emerged from their underground
molting hide-outs. New molters retain a smell of shed exoskeleton and
smell like a delicious treat to other hermit crabs. To prevent
cannibalism, you bathe them and wash off this molting smell. Remember that your hermit crab
cannot tolerate chlorine, so please be sure to dechlorinate the bath
water. The temperature of the water should be tepid, that is, about the
temperature of the surrounding room (not noticeably hot OR cold). For a
really special hermie bath, put in a couple drops of Stress Coat® (click on the name to find out
why). Most people bathe their hermit crabs in dishes, mixing bowls and
plastic containers. Take
your hermit crab from his
crabitat and try to get him to walk down your hand or arm into the bath
water. If he won't then you can slowly lower him into the bath by
himself. Set him at the bottom of the 'tub' so he is fully immersed.
After a minute, take him out of the bath, whether he comes out of the
shell or not. NEVER leave a hermit crab unattended in the bath, as
bathing makes them very active and they might crawl out and possibly
run away and get lost in your home. Drain the excess water from his
shell and allow him
to dry off. Some people have special 'playgrounds' for their crabs to
exercise in while drying off. Their 'drying off area' can be a simple
as a shoe box with a paper towel in it to absorb the excess moisture.
Place your dried-off hermie back
in his crabitat and sit back and watch. They are incredibly active
after their bath time and love to explore!
The introduction of crabs to a crabitat is an excellent time for you to
clean and re-order things. Use a kitchen strainer or fish net to strain
the sand to remove all crab poop, bits of exoskeleton and buried food.
Shake the sand out of the empty shells and replace the food in the food
dish. Put all their climbing toys back to where they were the week
before, or arrange them differently for a new look. I strongly advocate
that all crabitats be 'remodeled' occasionally to keep your crabs from
becoming bored with their environment.
Hermit crabs LOVE toys! They really enjoy climbing all over and hiding
in almost anything you can give them. There are many varieties of
'hermie toys' available in your average pet store. Some of the better
Dried choya (or cholla) wood (they
actually like to eat it too)
Driftwood in any shape or form
Coral, barnacles and sea fans (coral
also provides additional
Man-made 'hermie huts' for them to hide
Man-made 'half logs' also as hiding
Unpainted clay flower pots
So you see, there are all kinds of things you can put into your
crabs' tank to keep them interested and active. Just be careful and
any resinous (evergreen) wood into the crabitat. Crabs are arthropods
(in the same phylum as insects) and, just as cedar or pine irritates
moths, it also annoys hermit crabs.
A large (baseball-sized or larger) natural sponge in a dish with water
in it, close to or over the substrate covering the undertank heater is
VERY effective as a means of dispersing humidity into the air. The
sponge helps to 'pump' the humidity into the air better by providing a
larger surface from which the water evaporates. You might compare it to
how quickly a kitchen sponge dries out, as opposed to the time it takes
a dish of water to evaporate. The key to using the sponges is to have a
couple of them, so they may
be switched out on a regular basis to prevent any mold or bacterial
growth. A thorough rinse in hot water only and a short soak in a sea
salt solution, followed by a rinse in with some dechlorinated water
helps to clean the sponges. Squeeze out the extra water and allow them
to air dry. If additional disinfecting is needed, place the COMPLETELY
DRY sponge in the microwave for two minutes. Don't put it in the
microwave when they are moist (or even damp), or it will quickly shrink
up to nearly nothing! Large natural sponges can be expensive, and the
upkeep of them is
mandatory. Since they sit in water and the crabs crawl on them, they
are a prime breeding site for bacteria which could kill your crabs.
Anyone 'electing' to try this method needs to be aware that neglecting
the cleaning of the sponge on a regular basis is asking for problems.
There is a lot of information floating around about the proper way to
handle hermit crabs. Some people recommend picking the crab up by his
shell, and others recommend placing the crab on your outstretched palm.
The proper handling of hermit crabs is tricky; if you hold them by the
shell, they could reach around and pinch your fingers. If you place
them on your hand they could wander a ways and then grasp on to the
flesh between the thumb and forefinger.
Ouch! So I Shouldn't Hold
It is perfectly fine for you to hold your hermit crabs. However you
have to respect the crabs' ability to pinch. They are in fact CRABS and
most people associate crabs with claws. The key thing to remember when
you are holding your hermit crabs is to not take your eyes off of them.
If you are paying attention to your wandering crabbie, you cut down on
your chances of getting nipped and you also reduce the possibility that
the crab could escape from you and become "lost." When you pick up your
crab, always grasp him by the back of his shell.
NEVER pick up a crab from the front, or put a crab in your pocket and
close your fist around him. The crab will become alarmed and stick out
the claw and pinch. Pick up the crab carefully by his shell. If it is a
very active crab, be ready to quickly transfer him to another surface,
such as a sofa or bed. If you want to hold the crab in your hand, keep
an eye on it and make sure that it has room to both wander and also
that it seems to be comfortable. A good example of a happy, held hermit
crab is one that wanders from hand to hand without stopping. You do
this by placing one hand horizontally in front of the other hand,
giving the crab a continuous walking surface. Do not place your hands
fingertip to fingertip -- because there is not enough surface area and
the crab will become alarmed and pinch.
Handling Tips for New Crab
Be especially cautious with new crabs that you don't know, crabs that
have in most cases been abused at the pet store and have every right to
be pinchy. Think about it -- if someone picked you up and poked at you
all the time, you'd pinch too!
One of the reasons that new crabs pinch is because they are literally
starving to death and they automatically pinch onto things, in the vain
hope that they might snag some kind of food. A friend and I once went
into a pet store and found a jumbo crab who was pathetically pinching
the air about every 3 minutes and bringing up his empty claw to his
mouthparts. It was heartbreaking, and on the way home with us, he ate
an entire cracker all by himself.
A simple suggestion that plays on this is to feed your new crabs well,
and try not to play with them for the first few days they are living
with you. Use gloves if you are nervous. There is nothing wrong with
your skin from a crab that you don't know. Thinner gloves are better
because then you can feel the crab walking and get used to his weight
on your hand. If you're nervous about them however, thicker gloves are
fine. Start out by holding the crab over a bed or sofa, so if the crab
makes a move that startles you and you drop him, he will land on a soft
surface and not be harmed. Never allow a child to hold a new pet crab
in a kitchen, bathroom or
other areas with uncarpeted floors. A fall from three feet or more onto
a hard surface can be fatal (the crab's delicate internal organs
rupture). So please supervise all children with their new crabbies
until they are comfortable with the crab and respectful of the crushing
of his claws. On the one hand, a softball-sized hermit crab can
completely crush a No. 2 pencil in seconds with the large claw. On the
other hand, the large crabs are generally more gentle. Respect the
claws and you won't be caught by surprise.
Helping Children Get
Used to the Crabs
When I was a little girl, one of my favorite ways to play with my
hermies was to lay on my stomach and put my arms out in front of me in
a big circle, and put the crabs in the circle. They would crawl around
in there, and I got used to how their feelers and legs feel on my skin
(inner arms) without worrying too much about being pinched. If you have
plush carpeting you can put down a
blanket. Sometimes they try to escape underneath the armpit, but then
since they were on the floor already, I'd just move myself and make a
new circle around them, or roll them back into place.
often been asked "What is the single most critical element of
keeping land hermit crabs alive?" The answer to that question would
have to be keeping their environment humid. Land hermit crabs have
modified, stiffened gills which allow them to breathe air. They are
GILLS, however, and not lungs, so are not able to breathe as we do. The
air a hermit crab breathes has to be humid or the gills will dry out
and the crab will endure a long unpleasant death of suffocation,
similar to a human's death by dehydration. To make sure your crab does
not suffer this awful, very common fate,
make sure the humidity in your crabitat is kept at a steady humidity
level. Make sure of this by purchasing a humidity
gauge, and check it daily. Most humidity gauges read relative
humidity, so unless your gauge specifically says it reads [b]actual[/b]
humidity, you want to keep it at at least 70%. Many crabbers report
success with a humidity reading of between 70% and 80% relative
humidity. If you are forced to house your crabs in a plastic critter
use plastic wrap to cover the holes on the lid to trap humidity, or
place a warm moist towel over the lid for an immediate humidity boost.
If your crabs live in a glass aquarium, you can purchase a glass lid
for it at most pet stores. Since the glass lids store flat and out of
the way, many pet store employees might not be aware they stock them.
Go to this
site and print out a picture of the lid so they will know what you
are looking for. Note that the All Glass Aquarium Company also makes
most aquarium sizes and posts them (with their dimensions) here.
Look for your tank (or the want you want to buy) in the left-hand
margin and click on the appropriate link. This site comes in handy if
you happen upon a 'leaker' or used tank and are not sure of its size.
Do not overdo the humidity, however. Like all things, too much of it
can be bad for the crabs and can cause unhealthy bacteria to bloom in
their habitat. I have personally gone for months without a single crab
death, and I firmly believe that having adequate humidity in the tank
is the main reason. If your hermies are acting listless and bored,
check your humidity gauges, it might be that they are struggling for
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