I have 2 koi and 5 Goldie’s. My pond has 2 aeration stones,2 spitters,is shaded during the hottest part of the days and I have iris, cannas, water Lettuce ,lilies and even impatience doing wonderful. The water is nice and clear too but my crazy fish come to the top and smack their lips. It used to only happen at feeding time but now they do it often. WHY? Any advice or suggestions?