I have only been doing this fish thing for about a year. With my limited exp I first would have said RD because mine has been the boss from day 1 and still runs the tank that hes in. But when my dovii got to about 6in he really started getting nasty now hes 8.5'' and you cant come near his tank with out him going crazy. I even put him in a established tank once with some pretty tuff customers and with in a 60 seconds he had took over the tank and was ripping up a 9'' jag. So he lives all by himself for now until maybe some day I find him a lady.