Try some freeze dried krill, if you happen to get the larger ones you may have to crumble them up a little, my goldies love and supposedly it brightens the reds and oranges. I'm a faithful user of Aquadine and Hikari. But I use Blueridge gold formula for my bulk food for the Koi. My koi love cherrios, white rice, baby english peas,and oranges, limes and lemons but you have to feed them the pulp only. It's kind of messy but once they get used to it they love it.