Originally Posted by 54seaweed
I've had CBS over 5 years never seeing any type of aggressive behavior
no CBS are not tank cleaners in no means but yes they will clean parasites
and what not from a fish working like a car wash
as for has the op mentioned a mantis shrimp the answer is no
It was just suggested as an alternate cause
Coral Banded Shrimps do not clean parasites off of fish and indeed they can be mean. I had one and caught him with one of my fish that just happened by him. His claw had grabbed hold of the fishes tail and the fish was trying to shake him off... Needless to say I no longer have that shrimp..