Koi Aquaculture Techniques

Koi were originally bred in China between 2,000 and 3,000 years ago. Uncommon looking golden carp were bred together resulting in unique varieties. Today's commercially available koi are the result of breeders combining unusual color variations of the common carp in Japan and China to produce the many varieties commercially available today. It takes some expertise to breed colorful varieties of koi as some cross-breedings result in duller black and silver offspring rather than brightly colored ones.

  1. Pond selection

    • Koi need a pond environment to live happily and breed successfully. The pond size is based on the number of koi in the pond. The pond should be long enough for the koi to swim several body lengths without having to turn and needs to be deep enough for the koi to submerge to avoid predators. The recommended dimensions are at least 6 to 8 feet long and at least 45 inches deep. The pond needs a powerful filtration system that will remove the excess food and other organic materials from the pond to avoid health complications for the koi. If the pond is located in a colder climate, it needs a heater as well. The pond should have hiding places such as plants and rock ledges to ensure that the koi feel comfortable in their environment and can hide from potential predators. The system needs separate quarantine tanks for introducing new koi to the pond and separate breeding tanks for mating.

    Stocking the pond

    • The success of the koi pond is dependent on starting with good specimens. Stock the pond with healthy koi from a reputable breeder. Introduce new fish a few at a time, especially when the pond is new, to allow the biofiltration system to develop properly. Quarantine any new fish before adding them to the pond as koi are susceptible to a number of communicable diseases and parasites. Add new fish after you have observed that they do not have any health issues while quarantined. All of the koi in the pond should be inspected daily for health issues, diseases and parasites. Koi should only be handled using special nets that are made specifically for ornamental fish.

    Feeding

    • Feed your koi a commercially available koi diet with at least 30 percent protein and wheat germ as the carbohydrate base. Koi digest wheat germ better than other carbohydrate sources. As temperatures decrease in the fall and winter, koi eat less, so decrease the amount of food per feeding as temperatures go down.

    Breeding

    • Koi generally spawn in the spring. Koi will mate around a year of age, but more successful breedings occur around two years of age or older. It is important to have breeding tanks prepared with the same water chemistry that is in the pond so that you can isolate the breeding pair combinations that you want to mate. Separate males and females to avoid spontaneous spawning you do not want. Koi will consume their eggs after spawning, so remove the eggs and place them in separate tanks as soon as spawning occurs. Fry should not be placed in adult ponds until they are large enough to avoid being eaten.