We stock multiple varieties of koi food including our house blend. Koi food is not only designed to be nutritionally balanced, but to float, encouraging koi to the surface. When eating in a suspended manner, it is possible to check koi for parasites and ulcers. Koi will recognize the person feeding them and gather at feeding times. They can be trained to take food from one's hand. In the winter, their digestive systems slow to a halt, and they eat very little, perhaps no more than nibbles of algae from the bottom. Care should be taken. Proper oxygenation and off-gassing occurs during the winter months. Their appetites will not flourish again until the water becomes warm in the spring. When the temperature drops below 50°F (10°C), feeding, particularly with protein, is halted or the food can spoil in their stomachs, causing illness.