The Omega One line of foods are pretty good as well.
I feed all of my fish flakes as a staple but mix in frozen foods a few times a week as well. Bloodworms, brine shrimp, krill, plankton, glassworms and mysis shrimp are all on the menu. The discus also get mussel and beefheart. The plecs and cats and loaches also get algae wafers, shrimp pellets and veggies.
A varied diet will go a long way in keeping fish healthy and happy.
Bryan