Apocalypse - thanks for the response. Yes getting rid of Leo would be the easist solution. Lucky for her, she is the reason we have the tank/pond (I feel calling it a pond people think it is only for Koi).
I am not concerned about losing a few fish due to predation. Either Leo losses interest...
The pond is 6 foot by 4 foot by 3 foot high (water level) - above ground 2x4 framed and lined with a pond liner. It is run off a koi pond filter with uv. It is insulated and heated (900 watts); we are in Northern California in a valley (mild winter). It is only viewable from the top. A medium...