Yes you can essentially use most "fish" foods and all are safe for fish. I use koi food that has krill meal and shrimp meal and cost me like 25 bucks for 11lbs. I also use hikari and new spectrum but KOI food is excellent because the food contains asaxtasin or whatever it is called to get the reds out of the koi and does wonderful with flowerhorns.
I would stock up on that!