Our Privacy/Cookie Policy contains detailed information about the types of cookies & related technology on our site, and some ways to opt out. By using the site, you agree to the uses of cookies and other technology as outlined in our Policy, and to our Terms of Use.


How to Breed a Butterfly Koi

| Updated September 26, 2017

Things You'll Need

  • Male butterfly koi

  • Female butterfly koi

  • Worms

  • Flies

  • Child's pool

  • High protein koi food

Several outdoor ponds contain koi fish. This is because this versatile breed, which is actually a member of the carp family, can withstand the elements more easily than goldfish. Butterfly koi gain their distinction from other more common breeds of koi because of their long, flowing butterfly-like fins. Butterfly koi can grow to be 36 inches long and are a hybrid breed that has a mysterious past. There is no clear lineage, but many believe that these koi resulted from the marriage of a traditional koi and a goldfish.

Distinguish between the male and female butterfly koi. The males will generally be larger and fatter than the females.

Watch for the beginning of the butterfly koi fish mating season. This will generally occur in the late spring when the water temperature reaches 68 degrees Fahrenheit. The males will also display mating tubercles, which will appear as white spots on the fish’s head and pectoral fins.

Place the most desirable male and female butterfly koi into a separate pond. The koi with the brightest colors and eyes will produce the best offspring. The koi can be left together in the main pond to breed in a process called “flock spawning,” but this can produce an overabundance of fish.

Keep feeding the koi their regular meals during this time, or supplement the food with worms or flies.

Watch for the female koi to release eggs. This will occur after several days of mating rituals between the koi during which the male koi will chase the females. The males will immediately fertilize the eggs after they are laid.

Remove the eggs with a spawning mop immediately after the fertilization has occurred and place them into a separate pond or child’s pool. If left in the mating pond, the koi will eat the eggs.

Watch for the koi eggs to hatch, which will generally occur after three to seven days of incubation. The baby koi will immediately attach themselves to the pond walls for several days and eventually will swim to the top of the water. The baby koi do not require food during these first few days.

Feed the baby koi small chunks of fresh brine shrimp and high protein koi food that has been crushed into a fine powder.

Continue to feed the fry the koi powder until they are 1/2 inch in length. Small pellet koi food can then be given. The size of the food can increase until the fry are able to eat the same food as their parents. This is when the fry can be placed in the same area as the adult koi.