I was puzzled as to why some pond owners say they don't dissuade or take measures to keep herons from their ponds as they control the population. I asked recently whether the tiny minnows I was seeing might be mosquito fish or another type of minnow and many replied that they could be baby goldies but I was skeptical. After a week or so, it turned out they were baby goldfish (I have comets and koi in my pond). Today, I was down netting out leaves and happened to be standing where I could see just under the edge of a large growth of Parrots Feather and I think there must have been at least 45 goldfish of various sizes under there!!! As we are fortunate to have a circle about 9' across and a long end about 175' long, I can move some of the babies to the long end if necessary and I still don't want them eaten by herons but I don't guess it can de-populate the entire pond?? I still run them off when I see them but have tried to provide enough plant cover to provide hiding places.