hello I have a yellow lab and I just got a blue one that looks just like the yellow lab but .5 inch bigger. My yellow Cichlid was aggressive to the catfish and took chunks out of his fins but now the blue one is terrorizing the lab. I heard I could get more to get rid of aggression but I have a 20 long. Btw I have 75 gal filter on it and my water peramiters are perfect