If you are having a tank with water you should use a thermostat to heat the water. Thermostats are relatively cheap and you can get them from any aquariums. The temperature should be set at 24/25 c, and will automatically keep to that temperature once set. It's a good idea to get the thermostat set up before getting your crab as it takes some time to get the temperature right! You should use a mercury thermometer to get an accurate measurement!
Heat mat
If you are having a vivarium you should use a heat mat to heat the tank up. This means that a sensor must be placed in the tank at crabby height (be careful they do like to chew the wires!), you must have a thermostat set up also so that the heat doesn?t become too high or too low, once set it will constantly keep at that temperature. Again, the temperature should be 24/25c.
Please note the heatmat should NEVER be the same length as the tank, it should be SMALLER. The reason why is that crabs are cold blooded and therefore they need to warm their body temperature up by resting above the heatmat. If they become too hot they can cool their body temperature down by skuttling to a part of the tank where the heatmat isnt present and therefore the temperature in that area is cooler. I suggest putting the heatmat at the side of the tank you plann to make the sleeping/hiding area.
Lighting
If you have lighting in the tank this does contribute to the overall heat of the tank. When setting up the thermostat/heat mat, do it without the light on otherwise it will adjust too low and the crab will get cold at night when you turn the light off!
When getting a lid for your tank it should be heavy as rainbow crabs are crafty and strong and will easily life up the easier lids, all please gets lids that have the glass covers underneath the tank, for the main reasons that it stops the crab climbing up and burning himself and stops water vapour rising and causing serious damage!
