Any high-quality, premium food. A high quality dog food will list a specific meat source as it's first ingredient, for example deboned chicken or lamb meal. Meat by-products are NOT a good meat source, as the by-products usually consist of the scraps (ie fat, skin, etc.). You also want to look for a food that does not use corn gluten or wheat as a filler. Basically, any food you can purchase in a grocery store or Walmart is junk. A few of the brands that I highly recommend are Natural Balance, Canidae, California Naturals, Wellness, Innova, Solid Gold, and Merrick, to name a few. Petco carries a couple of those brands, but your best bet would be a feed store or a small local pet store. A good online store is PetFoodDirect.com. I highly recommend the websites I've recommended as sources. Ever since I started feeding my cats and dog premium food, they're coats are shinier, they're eyes are clearer. I can truely see a difference.