Wellllllll ive got both in my 46g right now. I got the BLUE CB and he isnt the nicest guy. Ususally if anything goes in his area he swings his claws in a tantrum and chases whatever came close. He's never came close except the fire shrimp. He(the fire shrimp) has no brain when it comes to when i feed my tank and he will always go by the CBS. Its actually funny because the FS always gets chased away. Granted my CBS isnt big yet. But so far so good. And if the CBS kills something, he will become the food of my mantis. Then again im not a fan of my FS stealing food off of my corals either. smh