Cyprinus carpio

Care Level




Reef Compatible


Plant Safe


Max Size

18 +

Minimum Tank Size






Water Conditions

36-90° F, KH 2-12, pH 6.8-7.2


General: Koi come in a plethora of colors including various shades of white, yellow, and orange. There are specific names for koi varieties; some popular ones include Kohaku, Chagoi, and Asagi. Most of the shipments Aquatics Unlimited receives will be scaleless and are officially called Doitsu koi. Another common variety we receive are butterfly koi. These elegantly-finned fish can live in captivity for 200 years and are sought after by many hobbyists.

Dimorphism: Male koi will often have fins that are more pointed compared to the rounded fins of females. Additionally, male koi will develop tubercules, which are small growths that are white in color, on their heads during the breeding season.

Fecundity: Although female koi may lay up to 100,000 eggs per clutch, many of them will not survive. Naturally, many of the eggs may fall victim to disease or even be consumed by the parents themselves. The rising temperatures of late Spring will trigger spawning behaviors, assuming the koi have reached full maturity. After reproduction has occurred, locate or remove any piece of spawning material such as plants and wood that the eggs have been laid on. Transfer the fertilized eggs to a separate tank with plenty of dissolved oxygen and maintain the same water temperature. Be sure to do very frequent (once per day), yet minor (10 percent) water changes for the first week. After three to seven days, the koi fry will have hatched. Make sure to keep up with water changes and maintain great overall water chemistry.

Water Chemistry: 36-90° F, KH 2-12, pH 6.8-7.2
Superior filtration, aeration, and plants can be viewed as essential to the pond hobby. Not only does filtration help remove harmful chemicals from the water, it also helps dissolve oxygen into the water column. A water pump, or even waterfall, can help do the same. A stagnant pond traps contaminants and fails to provide a safe living environment for some aquatic life. Help provide fish with shade and dissolved oxygen by adding live plants to any pond.

Compatibility: It is suggested to keep koi with their own kind.

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Author: Grant Stevens