Fire crabs are an endangered species that are currently located on the islands of Fiji. There can be severe consequences hurting one, including azkaban. You can have one as a pet, but you must have a license issued by the ministry of magic. You must have a wand in your hand at all times and have fire proof gloves and properly fitting clothes. To defend yourself, you can use the water spell or the knock back jinx. They shoot firs from their bottoms. Muggles want the shell for the diamonds the shell for money. Magical people want the shell because it lessens the brewing time on potions.