I would stay away from a common pleco due to their size and the amount of waste they produce. I have a 14" common in my 150g with severums, parrots, tin foil barbs and a clown knife.
In my 125g, I have 4 bristle nose plecos, firemouths, severums, several lace catfish and parrots and there's not near the amount of waste and all the fish are very active.