Hi, I dont have a pond myself but am posting this question for my mom. She has a large outdoor pond fed by an artesian well. She keeps many large koi in the pond and I have also seen turtles from a nearby river in her pond.

Recently she has had a problem with a blue heron sniping her koi. She already has a decoy heron by the pond but apparently it hasnt deterred it. Is there anything else she can do