A koi pond gets its name from these carp-type fish. Koi can soon destroy a pond filled with water plants so you should bear this in mind when planting. The best solution is to create a separate zone where the koi cannot swim.
The best depth for a koi pond is 100-120 cm, so that the fish can hibernate in a frost-free zone. You will also need a pond heater and several items of equipment to maintain clear, well-oxygenated water. The floor of a koi pond must be cleaned constantly. There are various devices for doing this, the biological filter being the most important. This type of filter uses bacteria to break down waste products. This is often done in combination with a UV filter which kills pathogens. Oxygen is artificially added to the water, surface water is kept clean with skimmers and the pond floor is preferably cleaned automatically.
This may involve a great deal of equipment but, in return, you will have a fantastic pond. These fish can recognise you and the members of your household, come up to play and even eat out of your hand! You can really build a relationship with them. After all, they are not just fish, they are koi!