I have tried a lot of so-called aggressive fish with tilapia but. but, nothing seems to survive. whether i put them together at a young age or older, nothing survives! Tank sizes didn't make a difference. From 55g. to 90g. to 110g. to 125g. same result. Unless someone know a super kick-ass cichlid that i don't know about, Tilapia Butterkoferis' rule! If you do, let ME know I have space and all size of tilapias'. #@?! some can't even co-exist with each other!