What if you had a large flat rock on the bottom of the pond, supported by smaller stones,
to make a large underwater "cave" the fish could hide under when the killer birds visit?
would that work? or would the fish not be smart enough to use it?
An extremely crude 2-second drawing:
Im considering building a pond this year..
I will likely have Heron issues as well..
I have seen them flying directly over our house before..