How to Artificially Propagate Koi

Move two sexually mature male and several female koi into the hatchery at least one day prior to the injection of hormones. Ensure the water in the hatchery is highly oxygenated by turning up the filtration system. Maintain a water temperature 68 to 71.6 degrees.

Dilute the tranquilizer in the water to create a solution of 1:10,000 dilution in the plastic bucket. Remove each fish individually and allow to swim in the bucket for 10 minutes. Remove the fish and place into the hatchery.

Mix dried carp pituitary gland in doses of .004 to .0045 grams per kg of body weight and 0.067628 fluid ounces of salt in water. The solution should be .65 percent salt. Insert the mix into a syringe. Inject in the back muscle of the female koi. Massage the muscle where the needle is inserted prior to withdrawing the needle. This will avoid leakage of the hormone.

Inject females with only 10 percent of the hormone 24 hours prior to planned removal of the eggs. Inject the remaining 90 percent 12 hours later. Cut the female open and suture the opening of her oviduct to prevent loss of eggs during ovulation. Suture the female's body to close.

Return the fish to the hatchery. Courtship will begin within 6 hours after the injection. Mating will commence with violent flapping in the water. Once mating has ended, allow another half hour to pass. Move fish into tranquilizing solution.

Dry the female with soft cloth. Open the sutures on the body and oviduct. Release the eggs into a plastic bowl or dish. Apply light pressure to the belly to express the eggs. Suture the fish and return her to clean water that is highly oxygenated.

Squeeze the belly of male fish lightly to express milt into test tubes.

Dump tranquilizing solution after fish have been returned to the hatchery and clean the bucket thoroughly.

Mix 1 quart of eggs with .010 to .020 grams of milt with a plastic spoon. Mix a solution of 1 quart of water, 4 grams of salt and 3 grams of urea. Add 3.38 ounces of the solution to the eggs and milt.

Strain off the fertilizing solution after 10 minutes. Mix 2 quarts of the water, salt and urea fertilizing solution and add to the egg and milt mixture. Stir intermittently and gently. Add eggs to empty plastic bucket. The eggs will swell as they fertilize. Change the fertilizing solution every 10 minutes for 1 hour.

Add tannic solution after the solution process has ended. After 10 seconds begin adding water and pouring off the solution until all the solution is removed and your are rinsing the eggs in clear water. Rinse the eggs three or four times.

Fill hatching jars with water. Gently pour the eggs into hatching jars; 20,000 eggs should fill one hatching jar. Increase the flow through the hatching jar to 2 quarts per minute after the first 10 hours in the jar to increase oxygen. As embryos develop more oxygen is needed. Increase again to 3 quarts per minute after another 4 hours.

Turn off the water flow on the second day. Add malachite green as soon as the water flow is turned off the hatching jars and allow to stand for 5 minutes. Turn the water flow back on. The malachite green prevents fungus from killing the embryos.

Investigate the hatching jars for hatched larvae. Once hatchlings are identified, turn off the water flow for 10 minutes to encourage the other larvae to hatch. The lack of oxygen will cause the larvae to stir from their eggs. Once all eggs have hatched, move the larvae to a larvae container. Start feeding larvae three or four days after hatching.