They do however, do best if a little green is added to thier diet. Discus need a variety of foods, not just one or two. It is alright to feed a base food, but do not just stick to this food and expect your discus to breed like guppies. Variety signals abundance to a discus, and will make them more apt to be healthy and spawn. There are many different types of food, such as prepared, frozen, and live.
Combinations are best, alternating which is fed when each day.
Prepared foods include flakes, pellets, and freeze-dried foods. Despite the rumor, discus will readily accept flakes, if properly introduced to them. They should readily accept most flakes, such as spiulina, cichlid flakes, Tetra Ruby, etc. Pellets are usually readily accepted, so long as they are small enough for the discus to eat and swallow. In my personal experience, they love Tetra Bits, which are higly nutritious as well.