I have heard of people keeping them in large set ups with mbuna, although I would make sure you have LOTS of solid small hiding places for the malawis to retreat to, mine is in with central/south americans and to be fair ignores all the smaller fish, and so far never gets bothered by any of the larger ones in the tank bar my pike, he is only around 8-9in at the moment though....the weird thing is my pike chases him and he runs like mad, yet the two kings of the tank (red devil and midas) completely ignore him....he can do whatever he likes wherever he likes as far as they are concerned, its almost as if they know not to upset him too much or they will very likely be toast once he gets bigger lol.