Pleco's with Oscars a very good combo, my tank is compleatly pristine with 2 plecos and an oscar, no uneaten foods around, the Pleco's take care of that
I have a 220 tank with 5 oscars, 2 platter size pacus.. one red tail shark, 2 pleco's and one red devil together.. they all get along great.. but we are taking the Oscars out shortly to a new tank simply because the Pacus need all the room they can get...