The Koi fish is defined by its colors; its natural tones are what give it character and vitality in your aquarium. So diminishing it would truly be a shame. That said, the best way to avoid that from happening is to make sure your Koi is healthier than ever. The Koi Gold Medium Pellet does just that. With nutrient-filled pellets, the diet ensures full color for fishes 6 to 12 inches long. Make sure your aquarium is as vibrant as possible with this essential item.