Yes, I have four comet and 2 gold fish died. Before they died I did notice those white spots on their scales, exactly like it was showing in this picture. The comet also have some dark spots right around and under their gills too. I did take the water for testing and it was all normal. I pump all the water out, clean the pond and pump all new water in...although these white spots did show up before I changed the water. Could it be ich?