If your going to do it make sure both the Discus and Angels are all cleaned personally by you. Sometimes when I have to move tanks or sterilize one I put my fish togethere and it may be for at least 10 days. I know my fish are not carrying anything and all my fish are at least a year old. I haven't brought anything new into my place in over 2 years. The Discus I got from Ryan back in April have still not entered my Hatchery and most likely won't until late 2006. But if you can avoid putting them togethere I would give them completly separate tanks becuase the Angels just eat way faster than the discus and you don't want to short change the Discus on food.