Predator Control
Some predators, such as raccoons, don't mind getting wet for a meal. Adding rock overhangs to your pond is not only a beautiful feature, but it can help prevent predators from reaching in and snacking on your koi.
You can also place a net across your pond (held down by rocks or stakes) to deter nighttime raccoon visitors. Try to keep the netting lifted off the water's surface so that your fish don't get caught.
Faux Logs and Faux Driftwoods
Protective Pond Netting

