As for the blue CRAYFISH (not lobster) idea... I think people were referring to Procambarus Alleni... they get like 5-7 inches I , I've seen different numbers and are from Florida (my avatar). I've bought them anywhere from 15.99 to 29.99 here in Maryland so the price may vary depending on your loaction. The better bet if you wanted one would be the species from Australia "Cherax quadricarinatus" because I believe they can get up to 10 inches and are also a very pretty blue but not as light blue, more of a darker color. If you were able to get your hands on one of the larger adults... he could easily fend for himself except during times of molting which could be countered by adding sufficient hiding areas. Not saying there's no chance if it going wrong... just adding a bit of a "better chance" for the idea of a crayfish. Good luck!