I have a 160L tank with an array of livebearers, corys, robin gouramis and other mild tempered fish. My water is quite hard (about 7.8 PH). Would Mbuna be suitable for this sort of aquarium. I would like to keep somthing a little more exotic than livebearers (like some sort of chichlid). I have thought about angel fish, but I do have some small tetras that I am rather fond ofm and I dont want them eaten. Any suggestions. I would like something that is not too aggressive, because I think I have finaly found a ballance in the tank, where no fish are being bullied.