Koi are Japanese carp that bred for their beautiful colours. Koi ponds add a tranquil and beautiful ornament to home gardens and business landscapes. Although humans do not raise koi for food, koi do have predators in the form of herons, raccoons and cats. Because a single koi can cost as much as £195, pond owners must guard their koi from predatory threats.
Leaf or bird netting will protect a pond from hungry beaks or claws. Stretch the netting across the surface of the pond. The netting allows enough room for koi to eat from the surface of the pond, but it prevents predators from lifting the koi out of the pond. The netting also helps keep the pond clear of leaves and other debris that can promote algae growth.
Float decoy carp in your pond to attract predators while live fish swim to the deep. Decoy fish attract predators by being non-responsive to fear. Predators will note the slow movement and seize the opportunity to feast easily. Though the predator will throw the decoy back, live koi will have had a chance to swim to safety.
Provide hiding places in your koi pond for somewhere safe to swim from predators. Breeze blocks, rocks and fish tunnels are viable options. Breeze blocks give fish a place to hide where they cannot be seen. Breeze blocks are too heavy for raccoons to lift from the water. Large rocks can be placed to create small saves for the fish to explore and hide. Small tunnels can be purchased from pond and water garden shops, but they may be easy for clever predators to overturn.
Add a fake alligator or grey heron to your pond. The sight of a predator or rival can deter many predators from fishing the waters of your koi pond. Such scare devices may not be permanent deterrents for predators that realise the devices are fake, but they can scare transitory predators looking for a new food source.