I've had a CBS and a pair of cleaner shrimp (L. amboinensis) in my 65 without a problem until I returned the CBS for other reasons. I also had a couple of peppermint shrimp (L. wurdemanni), and a blood shrimp (L. debelius) in with him. He didn't bother them, took a snap at them sometimes when they got too close to his overhang, but that would be the peak of aggressive behavior from him. My shrimps however, were all about the same size. I suspect that he will eat very small cleaners that are sometimes offered. I am currently on the lookout for a pair of Stenopus myself.