Lights off. Bubbler on. Some kind of plant cover so they aren't so easily seen. Do you have a waterfall? Keep it running. Anything to make it harder to see the fish in the water.
I might even go so far as to lay rolls of barbed wire fencing on the ground all around the pond. You have a small pond - it would be easy enough to do. Just put it out at dusk and let the little buggers try to walk on that!
I might even go so far as to lay rolls of barbed wire fencing on the ground all around the pond. You have a small pond - it would be easy enough to do. Just put it out at dusk and let the little buggers try to walk on that!