A non-native cherax species or most likely is a procambarus clarki that just moulted and is in the process of acquiring a bluish hue to age, substrate, food, genetics or a combo of all. I find it alarming that some people are charging hundreds of dollars for crayfish of certain colorations. Please, please do not engage in this practice. There is no crayfish worth hundreds for coloration as the coloration is variable (unless we are talking striped crays but even then consult an expert as this a very rare event and I wont even consider this an option as these crays are that rare). I know this is an older post but I had to comment. Save your money people!