hi- i got a 20 long with a 5" tilapia in there with a small 3" pleco, 1 2" filament barb, 1 2" red tail shark and 1 small festivum cichlid. they all get alonbgf pretty good. the tilapia is king though. he rules the roost and the fish know it. the festivum kinda chlls in the swords most of the day while the shark and barb chase each other alot. anyway, the tilapia would be broderline semi-aggressive territorial to peaceful territorial. i got a zoomed filter with sponge on the intake on one side and a whisper 10i on the other side for filtration while a sponge filter provides the bacterial core. what kind of fish would be good with him? thanks