Exactly how big of a crawdad have you ever seen? When I was a teenager I caught the biggest one I've seen in my life. It was at least 6" or 7" long, and I caught it in a little branch that's no bigger than 3' wide and 1' deep. It was crawling on the bank. I kept it as a pet in an old aquarium with several rocks in creek water. It disappeared one day, I imagine a raccoon got it. This crawdad's color was different than any other I've ever seen, it was red. All the other crawdads around here have always been dark brown, olive, or a blueish color, and not over 4" long. Has anybody seen a 6" crawdad in Tennessee, or is this fairly common. And is it common to see red crawdads? I understand there is an invasive species of crawdad that is illegal to bring into Tennessee and several other states, but I don't remember the name right off the bat. I'll look into that. That's one reason I'm reluctant to buy crawdads from bait shops.