You like your fish. You even have a favorite. So, don't choke out that baby. Pond aeration is one of the most vital components of a thriving koi pond. Even fish like a little bubbly in their water during the summer and especially in the winter. Some of our favorite pond aerators include Aquascape's products. They have a two disc version and for larger ponds, the Pond Air 4 Aeration Kit pumps air through four discs . For a showy display, set up Oase's floating light up fountain.