A more humane option, is to set up motion lights that are activated when predators come close to the fish pond.
Other humane options include a fake owl or snake to prevent other animals from coming near the pond. Many snakes eat certain types of birds that would visit the pond for fish, and some owls eat rodents and other small mammals.
If you use this option, you must move the fake animals every once in a while, so pond predators will not believe the animals are dead. Adding more lily pads in the pond, would provide more protection when using animal decoys.
To read more Options For Keeping Out Fish Pond Predators
