i've had a number of other fish including small blue gourmais with dats. if you have enough room and stuff, i dont see why it would work. especially, discus even grow faster then dats i think. also, an adult dat, would not be able to fit a full grown discus in its mouth. the only thing i would be worried about is getting the discus food, the dats will eat all of it before the discus. also, the tetras wont last as stated.