Discus aren't nearly as difficult to keep as they are made out to be. Although it's not a good idea for the inexperienced hobbyist to keep them, I wouldn't say it's reserved solely for the experts. Mine are very happy and I don't use RO water or anything like that. It's a 45G heavily planted tank, with a whisper power filter on it that uses peat as the media. I change the water only once a week, and they are very happy and healthy.