I checked out that site above a while back and ruled it out because they are giving bad info. These crabs do not do well in fresh water. In fact no crab, save for a thai micro crab, will thrive in freshwater. This site is better since they keep them in brackish water but they don't allow them access to land which also greatly shortens their life span:
Buy Aquarium Crabs for Sale at AquariumFish.net where Shopping for a Freshwater Crab is Easy.. Also you have to buy atleast 3 and who knows what you will get as far as the sex. That doesn't work for me because after finding my favorite male crab of all time, my gentle giant, brutally murdered by his new male tank mate, I will never have 2 males again.