IME, mbus will generally do fine in a predatory community setting as long as they aren't kept with bottom dwellers or other sedentary fish. I currently keep my 20" mbu in a 360 gallon tank along with a 20" jardini, two 16-18" temensis, seven 14-17" redtail brycon, two 14-16" dorado, two 8-10" Indo dats, and a 10" paratilapia small spot. The only problems I've ever experienced with my mbus have been nipping the fins of catfish and bichirs and aggression between two mbus.