[mattawan_cichlid]

Hey, I don't really have any experience, but what I would suggest is probably just sticking with the 3 species you currently have. The yellow labs and pearlmutts are mbuna, so slightly more aggressive, but they are less aggressive than others. How many of each do you have right now?

 

[mattawan_cichlid]

I know Red Empress really needs a bigger tank than just 55, more like 75-100 but if your set on 55 there probably isn't any changing your mind lol