i have had a golden flake in my system for about six years now. He picks and grazes constantly, and eats about any thing he finds in the tank. He is number three in the pecking order underneath an emperator and majestic angel but he doesnt get messed with much. I have a large shaded area of live rock in one of my sumps so i am able to feed sponges once or twice a month. I also recycle a lot of algae from my sumps back through the angels. However, the only out side food i give them is 3/4 sheet of nori and a lump of shredded squid or fresh clam in the morning every day. They all seem to stay healthy, fat and more importantly very regular with this regime. In the past before i swiched to this feeding regime i would loose many fish at the one or two year mark. Now, almost all my fish are over six years old and going strong. I believe the heavy nori feedings are a major factor in their contnued long term sucess. Here is some recent video of the tank that i posted on the coral forums.
http://www.youtube.com/watch?v=cbetfeg3r3a