The biggest difference here is the fact that the fish must go to the shrimp in n order to becleaned. I have,in the past, introduced a Powder Blue and Powder Brown at the same time. They both icked up and the brown went to the shrimp to be cleaned and the Blue wouldn't. Needless to say, I still have the Brown and the Blue has went on to the great tank in the sky. The Wras is always out stalking the fish, thus bringing the cleaner to the fish that needs it. This is why the wrasses are a better bet, I still keep a cleaner shrimp in my tanks though. Cool shrimp that is not nocturnal and does a job all day long.