Electric fish, there are few types of catfish and the eel of course. It might even prove to be funny if you could get a few, electric cats are illegal in some states, and I have no idea on eels or availabilities or what kind of environment considerations it would take to keep them in your pond.
I would love to see what the outcome would be when the old heron went after one.
Yes I know this is a moronic idea
"I hate to advocate the use of drugs, alcohol, violence, or insanity to anyone, but they always worked for me." - Hunter S. Thompson
Ad astra per aspera
Nihil curo de ista tua stulta superstitione.