I feed my goldfish Hikari Lionhead, homemade gel foods (comprise mostly veggies), Mazuri gel foods, plant cuttings, bloodworms, shrimp pellets and the occasional shrimps. My homemade gel foods make up most of the menu though since it includes sardines, multivitamins, calcium, acidophilus, etc. I combine now my Mazuri powder with the homemade gel food.
Gravel is fine but I personally hate gravel as I had to vacuum it and I don't like to waste time over it anymore so my goldfish tanks are simply barebottom with plants kept in pots.