  
*Please note sadly at the present time I am not well enough to respond to any emails sent - please use the "crab forum" link to post messages to other crab keepers!*
Rainbow crabs are land crabs. They should be kept in a dry land tank with sand and a large deep water bowl (with rocks so that the crab can climb out) the water bowl should take up a quarter of the land space. Cardisoma armatum is the name given to Rainbow crabs; this breed comes originally from Africa where they live on beach coasts. Unfortunately, there is little information known on rainbow crabs so I thought I would create this website in order to provide as much information as I can. This information is relevant to most land crabs that need to climb out of the water to breathe. If you have hermit crabs the vivuruim information is relevant with the only change being that they need a shallow water dish so that they cannot drown. Firstly, something which is very important is that Rainbow Crabs must not under any circumstances be kept with other crabs, even other rainbow crabs - yes I know aquariams keep them together but they shouldn't. Rainbow crabs may seem to get on well together when they are young but as they reach sexual maturity they will become very aggressive to one another. This breed are very solitary and will fight (even to the death) if put with others. The only time they are seen together is during mating. The problem is that aquariams tell people that they can be kept in pairs and that their crabs have never fought. Young crabs will not fight, but within a few months they will end up fighting to the death. Avoid this situation, do not get more than one crab
Another question I am often asked is whether or not a pet crab can be kept with fish in the tank, the answer is no! Crabs eat fish, so naturally by putting a crab in a tank with fish it will kill them, which is cruel so please dont be tempted to do this for the sake of making the tank look pretty.
This site is always updating so please return again :)
Crabs are endothermic which means that they are cold blooded and require heat from another source. If they become too hot or too cold they will die. This is why either a thermostate or a heat mat is required with the tank, but there must be areas that they crab can escape to in order to lower its body temperature if it feels it needs to.
This breed can live for about 5-7 years and often crabs are at least one year old when they are bought. Unfortantely this hasnt been proved, and the crabs ages seem to vary. The temperature should be set at 24.5ºc with an underwater heater (if in a water tank) or a heat mat placed under the tank (not in! - very dangerous) if in a vivarium. If using a water heater a thermometer (in which you are gageing the temperature) should be set on the other side of the tank to ensure an even temperature (with rocks so that the rainbow crab can climb out of the water). If using a heat mat please ensure that the heat mat is underneath the tank not in the tank and that the heat mat is not the same length of the tank, the reason why is that the crab needs cooler places in the tank so that it can cool down, the heat mat can go at either one end of the tank or in the center. Please read on...
 
It is important to find out if your crab lived in saline or freshwater environment prior to buying it. My crab was raised in freshwater and 4 years on he is both happy and healthy and has never been in saline (salt) water, however if your crab has been raised in saline water and is then added to freshwater it will die, it is important to find this information out.
To start with
Crabs shed their shell and armour often when they are young. They should not be disturbed during this time as they are very soft and vulnerable, please do not be tempted to take photos as this can cost the crabs its life due to additional stress. It is often a good idea to have a cuttle fish (like the ones you give to budgies) always available in the tank so that the crab can get additional calcium if it needs to (calcium is needed for a strong shell). You may find that prior to shedding your crab may not eat up to 3 months before! This is in preparation of shedding. The shell and legs often change colour also. A lot of food should be offered after shedding so that the crab can regain its strength.
With a new crab who is shedding regularly it is wise to buy a spacious tank and fill it 1/3rd with water. This water should be heated with a thermostate, which controls the temperature. The water will ensure that the crab can slide out of its shell more easily. The crab must have plenty of rocks or wood (such as bog wood) to climb out of the water (this breed are land crabs and need to breathe air). My crab was happy with this for 2 years, after that he's regularly shedding stopped and I changed the tank into a vivarium, which I found out was a more suitable environment for the adult crab. When rainbow crabs are young they will tend to live in little rock pools, firstly, to be close to the water and secondly as they are very vunerable to predators. This is why at a young age I suggest having a tank with water, instead of a vivuruim.
If you are having the tank 1/3rd full with water (such as the photo below) there must be spaces for your crab to escape and climb out as they need fresh air to breathe they cannot get this from the water itself. It is also important that you have a pump (because of bacteria from decaying fish). The water should be cleaned out every 2 weeks (no more - you will take all the good bacteria out and no less - too much of the bad bacteria will breed and kill your crab) also only ever remove 20% of the water in any one water change because it could make your crab ill to do so. If you opt for a vivuruim the water should be changed daily because no pump will be circulating the water.
Vivarium
 When your crab reaches 1/2 years of age the tank should be changed into a vivurium. Rainbow crabs are land crabs and as they reach adulthood they prefer this setup. When the crab is young it naturally feels safer in a water tank and being surrounded with water also makes the shedding process easier with less risk of legs being torn off. When maturity begins the crab naturally wants to explore new areas and so the tank should be filled with sand and also have a water area. The sand should be mostly dry, some people find (as in my case) the heat mat produces enough condensation for the sand to be damp in places and easier for the crab to dig in, others find using a hand water spray is a good method to use to ensure that your crab can dig and build tunnels in the sand. Naturally research is very limited and the only thing I could find out is that this breed are land crabs and usually live in beaches tunnelling up to a meter under the sand. It was a big step to change from a tank to a vivarium but I decided it would be best for him and 13 months on he is much happier in this environment.
This photo is of he's new vivarium. As u can see this isn't filled with water as in the other photo. After Ritchie (my crab) stopped shedding as often as he used to he no longer needed to have a lot of water and research made me set up this tank. It is filled with both sand and bark, it has cork wood in it, which provides the crab with hiding shelters and something to climb on, but is light so that if it fell on the crab it would not injury it. The tank also has a large water pond that is deep so my crab could submerge himself in but would stull find it easy to climb out of (crabs will die unless they can keep their lungs wet, they do this by submerging themselves in water). Equally, however, they breathe fresh air and will also die if they have no access to it. They must have deep water and it must be easy for the crab to climb out of (i.e stepped edges or rocks). If you have hermit crabs they must have very shallow water so that they do not drown. Personally, I found that a large glass mixing bowl looked both decorative and provide a adequate amount of space even with rocks placed inside, so that the crab can climb in and out. The warning I must give you however, is that glass mixing bowls can not be taken in and out of the tank, once they have been put in the tank they must stay there and changing of water must also take place inside the tank, without lifting the bowl (scooping the water out), glass will crack if it contains water or if it is dropped causing injury to both yourself and your crab. Plastic water dishes or ice cream tubs are fine to use and are safer!
I believe it is important to every few months change the layout inside the tank, as with all exotic species they aren't really meant to be captive and as a result often get bored and destructive, so keep your crabs minds stimulated add extra bits of wood or move in different objects, keep them intrested in their environment!
Important info
If you have a water tank with 1/3rd water in it you must not have a heat mat!!! It is very dangerous! If the tank leaks it will set fire to your house! Tanks with water in them must have a thermostate, tanks with a water container inside them (vivuruim) are safe to have heat mats but keep a close eye out that the water container and the tank never leak!
Hiding Places
Crabs must have plenty of hiding places both in a tank and vivarium environment. As the photo shows I have wooden cork logs which go in the tank. These are great as they are both light and hollow which means no crushed crabbies! It also means a nice dark hidding place that mr crabby can sleep under during the day (crabs are nocturnal).
Thank you to freewebs.com for their hosting of this website.
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