well, it would depend on a lot of things. if you had a large tank say 90 gallons and you had a group of discus, either only 1, a breeding pair, or a group of at least 6, and 1 angel or a group of about 5 or more, then you should be okay. both of these fish can be aggressive when kept with just a few of each other. having a group would spread out agression. also, i would watch the discus and angels at feeding time since angels are a bit more "aggressive" eaters and discus will pick at thier food until satisfied. other than that they are compatible.