Hi DavidR,
A heron mostly knows his way with goldfish, because he does not have to wear spectacles to see it. Good you do not have that many as we have here in Holland, because they would have emptied your pond in no time. Funny is that we have plenty of heron here, and storks almost became extinct (we have them in captivity), in Poland it is just the other way around plenty of stork, heron (czapla) almost went extinct there.
polonus