The SCARECROW to the rescue!
I have a small Koi pond that I constructed less than a year ago. Soon after populating it with a number of fish, we lost our first (and most favorite one) to a predator. We thought it might have been a Heron but now it seems most likely to have been a Raccoon. I then installed a screen over the pond but neglected to secure it well. Another Koi turned up missing and the screen had been dragged across our back yard.
It was then that I installed the Scarecrow and secured the screen in a
better manner. Since that time there have been no more nocturnal
visitors and I fully credit the Scarecrow with providing the protection
that I needed. I only wish that I had known of that wonderful product
much earlier and spared the loss of a couple of favorites.
In the words of the good people who make the Scarecrow:
"Protect your garden or pond from unwanted animal intruders.
The Scarecrow motion activated sprinkler instantly releases a short but startling burst of water when it detects animals. The sudden water, movement and noise scare animals away, and help teach them to avoid the area in the future."