Moon crabs

Question
Hello, I know this may sound weird but seeing as you know about hermit crabs I thought you may be able to help me with this. In the pet store last night i saw these "moon Crabs" they are about 4 inches wide right now and are land crabs that are sort of purple/orange, the pet store guys said they'd get 8 inches long, eat dead fish, fruits/veggies and hermit crabs pellets & need to be kept moist, if you know anything about these please let me know, I am wanting to get 2/3 but can't find any info on them, I will email yuou questions once I know weather or not you know anything about them, thansk in advance.

Answer
Hi,
thank you for your question.
I'm afraid I don't know much about moon crabs. The most important thing is to make sure the crabs in the pet shop are really moon crabs, Matuta lunaris. Pet shops often don't have a clue what they are actually selling and just make up fancy names.
Since you said that the crabs are purple-orange, I suspect they are either Cardisoma armatum (aka Rainbow Crab) or Gecarcinus ruricola (aka Halloween crabs/Red Crab). Moon crabs are whitish-grey, maybe a bit blueish.
Please try to find out the scientific name, a photo would also be helpful. I hope I can be of more help then
Jennifer