Really? I always thought they were pretty hardy and I've had no trouble with mine. I usually feed every day, sometimes every other day, and I use a variety of Formula 1, Brine Flakes, New Spectrum pellets, and an assortment of frozen food. I do usually crush a flake up a little bit so there are smaller pieces for him, but he eats anything and everything that goes in the tank!
Yellow Fish (my son named him...very creative huh?) was the first fish I added after my cycle completed back in February. Doesn't swim much but is almost always in view and perched on something so he is my favorite!