Koi are large and opportunistic eaters, making them amenable to being hand-fed. Many fish will swim up to your hand in an effort to get fed first. One of the best ways to get to know these fish is to pay attention to the unique characteristics each one displays. Maybe the koi will get names, too. Floating koi fish pellets can be used to bring your koi fish to the surface, where you can interact with them and check for any issues.