I would not put any Plecos with Discus. I had just about all kinds of plecos before, including the Queen Arabesque. I've seen Discus killed by plecos sucking on their sides, while they sleep. Believe me, it is like vampires. This time I believe it was a Royal Pleco. Needless to say, I remove them all from my Discus tanks. If you want something to help you with the cleaning of the tank, try Chinese Otocynclus or Green Corydoras.