Windsor fish hatchery recommends feeding wheat germ & or algae in the cooler months of the year to prevent problems caused by undigested food.
In cooler water Koi fish & goldfish metabolism slows down, they can only really digest their food in the warmest part of the day.
* Feed you koi in the morning so they have all day to digest their food
* halve their intake from summer feeding.
* don't feed in the late afternoon
Can be fed in Summer for variety