Koi Care Guide

Koi are relatively hardy, but they require careful attention to water quality and habitat. In outdoor ponds, koi benefit from natural filtration and plenty of space. Ponds should be equipped with a strong filtration system to handle their waste production, and regular water changes are necessary to maintain a healthy environment. In a pond, koi thrive in pH levels between 7.0 and 8.5, and they need plenty of oxygen, which can be provided by water circulation and aeration devices.

Feeding koi is simple, as they are omnivorous. A balanced diet includes high-quality koi pellets, fresh vegetables, and even fruits like watermelon. In ponds, koi will also feed on algae, insect larvae, and other natural sources of food. During the colder months, when temperatures drop below 10°C, koi enter a state of torpor, and their metabolism slows. At this point, feeding should be reduced or stopped until the water warms again.

Koi can live harmoniously with other large, cold-water fish like goldfish. However, smaller fish may be eaten, especially if they fit in the koi’s mouth. In ponds, koi have plenty of space to coexist with compatible species, whereas in aquariums, the cramped environment can lead to stress and aggression. Koi are known for their peaceful nature but will require enough space to swim freely to avoid territorial disputes, particularly in smaller settings.