April 11

Sarah Robertson

Complete Guide on How to Breed Koi Fish?

If you own koi fish, you may have thought about breeding them at some point. The prospect of breeding koi can be both exciting and daunting, but with a little bit of knowledge and preparation, it can be a relatively easy process. 

Koi fish are not easy to breed. It can be quite difficult to get them to mate and produce offspring. Several factors can influence the breeding process, including the time of year, water temperature, and the availability of food. If you're thinking about how to breed koi fish, it's important to do your research and make sure you have the right conditions in place. With a little bit of patience and effort, you can create a beautiful koi pond with healthy and happy fish!

In this article, we will go over the basics of koi fish breeding, from how to prepare your pond for breeding to what you need to do to care for the young fry.

Tips for Breeding Koi Fish

Here are a few tips to help you breed Koi fish:

In the Same Pond, Keep Both Male and Female Koi Fish.

To breed koi fish, you'll need at least one female and one male. Many people, however, make the mistake of confusing a female and a male koi fish. The male koi fish is more slender, while the female is rounded in appearance. In addition, the fins of the male koi fish near its head are more defined than those of the female.

You Will Need to Use Parents From the Same Variety.

When choosing parents, it's important to select koi fish from the same variety. This will help ensure that the fry inherits the desired traits from their parents. For example, if you want to breed koi with long fins, make sure both the male and female have long fins.

Make Sure the Koi Fish Are of Appropriate Age

Koi fish are most likely to mate and produce offspring if they are between the ages of 3 and 6 years old. However, in some cases, koi fish may also produce baby koi fish as they get older.

Provide the Right Conditions for Spawning.

In order to breed koi fish, you'll need to provide the right conditions for spawning. This includes keeping the water temperature at around 68 degrees Fahrenheit and making sure there is plenty of food available. The water quality should also be good.

Make Sure You Feed Your Koi Fish at the Correct Intervals.

Make sure the koi fish are well-fed before, during, and after you intend to breed them. It is essential to feed them at least four times a day while breeding koi because they require a lot of energy. Koi owners must replenish their vitality so that they may produce high-quality baby koi in no time.

Give Your Koi Ample Privacy.

Like human beings, koi fish require space and privacy when attempting to breed. Because the koi fish take some time to breed, do not be in a rush to see them do so. Allow them time, and allow them to feel encouraged by one another's mating.

Keep the Pond Clean

Make sure the water is clean and suitable for Koi fish breeding. It's critical to have a dependable water filtration system in place to maintain the water clean for spawning. This allows debris to be filtered from the water and kept dirt-free at all times.

Give the Fish a Place to Lay Their Eggs

You'll need a surface for the koi fish to lay their eggs because unhatched off-springs are delicate and must be incubated in temperatures of 15 to 20 degrees Celsius. A fry mat is advised, but you may also use something similar. This lets you view the eggs more clearly. You could want to keep the parents away from the eggs since they might consume their own offspring.

Koi Fish

Advantages of Koi Fish Breeding

  • It's a cheap approach to growing your koi empire.
  • You may earn some fast money by doing so.
  • This is a wonderful method to learn more about koi and fishkeeping. It's extremely engaging and has a lot of information to absorb as you research, read, and interact with other koi enthusiasts.
  • Once you've mastered the art of koi fish breeding, you may use it to raise other species of fish.

Disadvantages of Koi Fish Breeding

  • It's a time-consuming procedure that requires a lot of effort.
  • It necessitates a significant financial investment.
  • To maintain baby koi fish, you'll need to increase the size of your tank.
  • Your female koi fish may get sick.
  • Even though thousands of Kois are created each year through koi fish breeding. Many perish before the culling procedure (selective reduction) begins.

The Necessary Tools for Koi Fish Breeding

Outside of the pond, you'll need several tanks and other materials to breed koi.

  • You'll need at least two tanks: one for breeding and another for medical care. Both must be able to hold at least 200 gallons of water.
  • Filters, water pumps, heaters, air pumps, airstones, and net covers must be purchased separately for each tank.
  • For the breeding tank, you'll need spawning brushes.


After you've gathered all of your materials, it's time to look for the ideal location. The job might take weeks and may be hard to relocate once it's in full swing. Check to see whether the site is accessible and maneuverable, with no obstructions to access or movement. The location should also be near a water source and not subject to direct sunlight.

When Is Breeding Season?

When the weather (or tank) warms up, koi will multiply. It's difficult to identify any true “season” since ideal conditions may vary from nation to nation, state to state, and even among individual fish. In most regions, outdoor breeding begins when the water temperature reaches 68 degrees Fahrenheit.

Preparing the Pair for Breeding

Always Choose healthy fish. The male should be at least 3 years old, whereas the best age range for females is between 5 and 8 years (there is no upper limit for males).

Fill the breeding tank with water up to a foot below the tank's top. Place the female, equipment for spawning brushes, and spawning brushes in the tank.

Expose her to a springlike environment. If the area has enough natural light, it's an excellent idea to provide it; otherwise, the tanks can be put outside. You may also use artificial lights with timers if you like.

Once she's ready, the female will explore nesting locations (such as spawning mats). You may now add the male to the breeding tank and cover it with netting at this point.

What Happens During Breeding?

Koi romance takes a few hours, and the male is put with the female in the late afternoon by experienced breeders. Spawning normally occurs just before dawn. Keep an eye on him for a while to ensure he isn't overly aggressive. Koi mating may be boisterous, but some males go over the line and need to be removed for the female's protection.

  • When the female is ready, she emits a pheromone to attract the male.
  • He guides her to the spawning sites.
  • The female releases her first batch of eggs, and the male spits out sperm.
  • The parents then eat some eggs, which are a highly nutritious form of natural culling.
  • The female repeats the cycle until she has no more eggs to release. Take out the male at this time or he could eat too much.
Koi Eggs

How to Care for Koi Eggs? 

After mating, the male is released back into his pond. To rest and receive medical treatment for any physical harm, the female is kept in a hospital tank for a few days. Neither gender is interested in the eggs or infants when they first hatch. When the adults are removed, the breeding tank becomes your nursery tank.

Here Are Some Factors to Consider While Caring for Koi Eggs:2

  • Water conditions and temperature must be maintained at their ideal levels.
  • Pay special attention to ammonia levels. A value of zero is ideal, while anything greater necessitates a water change. Replace 20 to 30 percent of the water over an hour, or use an ammonia reducing product.
  • It's a good idea to do a water change since the mating process leaves an odor and sometimes clouds the water.
  • When water levels drop during a change, don't let the eggs come in contact with air.
  • Turn off the water filter, then distribute airstones evenly throughout the tank.
  • Remove nonfertilized eggs, which will be white and sometimes fuzzy.
  • Water should be kept stable and you shouldn't worry about a little algae bloom; it's a baby koi's delight.
  • Within 3 to 6 days after fertilization, the eggs hatch.

Breeding Koi in a Pond 

This simpler choice entails no extra tanks. When the weather and water conditions are appropriate, koi will breed. However, keep in mind that only a small proportion of the fry survive this process. Adult koi scoop up any eggs or newborns they can find.

If you only want a few new koi, this may not be an issue. Provide hiding places for the infants and nesting sites for the parents. Use ornamental plants and spawning brushes to hide the pond's edge. Plastic plants can also be used in place of actual ones.

How To Breed Koi Fish?

Kois can be a lot of fun to breed, and it's a time-consuming process. It is critical to mate koi that display the physical qualities you desire in offspring for a commercial purpose. To improve the number of koi eggs that produce and survive their early weeks, keep the pond clean and free from predators.

1. Choosing Koi to Breed

  • Choose koi that are at least three years old. Koi don't reach puberty until they are approximately three years old. To improve the chances of them koi fish breeding and producing high-quality kids, wait till they're three years old.

When they are three years old, koi reach a length of 10 inches (25 cm).

  • At least 1 male and 1 female must be kept in the mating pond. Male and female koi are quite similar in appearance. Male koi, on the other hand, have tiny white bumps on their pectoral fins and heads during mating season. Remove any koi you don't want to breed from the pond; otherwise, you'll get undesirable baby koi.

Once they begin breeding, males can be recognized by the fact that they chase females around the pond.

It is not harmful to have many male koi in the same pond.

  • Select koi with characteristics you want to imitate. Consider the characteristics you wish to see in your koi offspring. Choose koi that have the fin form you desire if you want a particular type of fin. Choose koi with healthy-looking scales and at least 10 inches (25 cm) long, no matter what physical features you desire.

If you're looking for a certain hue, go with koi parents that exhibit it.

2. Making the Right Conditions for Breeding

  • Kois are best bred in the spring or early summer. Koi breed when it is warm and the water temperature has risen. Because koi can produce up to 1 million eggs, you must be prepared for that.

If you don't have the proper conditions or enough capacity for baby koi, consider removing the males from the pond during this time. You'll need a pond that's 3 feet deep and 6 feet long by 8 feet wide to accommodate 5 koi. You'll need a larger pond for additional koi.

  • To keep the water clean, use a filtration system. A clean pond is essential for the health of koi and their offspring. Use a specialized koi pond filtration system to keep the water clean while they're breeding. These might be pricey, but they are necessary for breeding.

For about US$200-US$2000, pond filtration equipment may be purchased from pet stores or specialist fish dealers.

If your pond is seriously filthy or covered with algae, it will need to be completely cleaned.

  • Remove any debris or predators from the water using a skimmer net. To keep the eggs safe, predators (such as other fish) and waste should be removed from the pond. To remove anything that may harm the koi, a skimmer net or a comparable scoop device can be utilized.

Cover your pond with netting to keep koi safe if cats or birds are approaching. To protect the koi, cover the pond with a large piece of netting and hang it above using large rocks.

  • Feed your koi 4 times a day while you are attempting to breed them. To improve the odds of a koi mating, feed them well for one month before you breed them. The koi should be fed as much as they can consume in five minutes. Wholemeal bread, oranges, and whole lettuce are dietary options that are high in nutrients.

Feed your koi a greater quantity of protein, since this helps support their bodies for breeding. Protein supplements can be found at a pet shop. Also, follow the feeding instructions on the back of the packet.

  • In the pond, lay a fry mat. This is a flat, sticky mat that serves as a nest for the koi to lay their eggs on. If the koi are unable to locate a suitable location to deposit their eggs, they will not always mate. The mat should be placed in an apparent location at the pond's bottom.

Purchase a fry mat from a pet store or a fish specialty shop.

  • Prepare a special tank for the adult koi. If you want to produce a large number of koi, it is critical to get rid of the adult fish because they will consume many of the eggs. The tank should be clean and have a filter system in place.

Leave the adults in the pond if you are attempting to breed a small number of koi.

Purchase a koi tank from a pet store. You'll need an aquarium of at least 100 gallons (380 L) for two koi.

  • Allow the koi to mate. The pair may be together for a few days or weeks. If the koi don't appear to be attracted to each other at first, don't worry. A storm, a full moon, or a change in air temperature might help stimulate the koi to mate.

When the koi have mated, a froth will develop on the surface of the water and their eggs will be visible on the fry mat.

Caring for Young Koi

3. Caring for Young Koi

  • Examine the surface of the water for any sign of froth or scum. This shows that the egg has been released. The spawns are then fertilized by the male koi, and the eggs are formed.

After about 4 days, the eggs will hatch.

If you are breeding koi for profit, remove the parents from the pond as soon as you notice eggs or froth on the water.

  • After 10 days, feed the baby koi with powdered koi pellets. Gather together the crushed koi pellets and place them in a blender or mortar and pestle. Sprinkle the powder over the pond. Pour enough powder into the pond to keep the fish entertained for approximately 5 minutes. Feed your koi four times each day.

Continue to offer the baby koi powdered food until they are four weeks old.

Over time, You'll figure out how much food the baby koi need during each 5-minute feeding session.

It might take a few days for the koi to get acclimated to eating the powdered food.

Feed the fish 10 days after you discover the eggs.

  • To help your koi grow, increase the food intake after they've reached a month old. Start feeding the crumb pieces once your koi are four weeks old. You'll still need to break up the pellets, but they won't have to be in a fine powder any longer.
  • Any weakfish that are unable to breed should be culled. If you want to commercialize koi fish breeding, you'll need to get rid of some of them. Determine which koi are tiny, have physical impairments or aren't in the color patterns you desire.

Koi can be culled at any age; however, it is best to wait until their patterns appear before deciding whether or not you want to keep the koi with your favorite colorings.

  • When the baby koi are 3 inches (7.6 cm) long, reintroduce the parent koi. When the baby koi begin to grow larger, the parent koi become friendly with their offspring. This is a good time to reintroduce the parents if you've taken them out of the pond.

The average age for a baby koi to reach 3 inches (7.6 cm) is about 3 months.


When Do Koi Spawn?

The spawning season usually starts in the early hours of May and June. The males will start following and showing interest to the most receptive and fertile female as the koi approach spawning.

How Do You Set Up a Koi Breeding Pond?

To induce your koi to breed, you must set the proper ambiance. A clean pond is critical for the health of the koi and their offspring. Use a specialized koi pond filtering system to keep the water clear throughout the koi fish breeding season. These are pricey, but they are required for breeding.

How Do You Know When Koi Are Spawning?

Before the actual day of spawning, you will frequently see one or more males take an interest in a female and follow her around the pond for a day or 2. The male koi begin their spawning activities early in the morning, fiercely pursuing and nudging the female around the pond's shallows or margins.

What Do You Do After Koi Spawn? 

After spawning, you may add ropes to the pond for the fish to lay their eggs on, and once you see the coil has devoured all of their eggs, take away the ropes from the pond.

Once you have seen eggs on the surface of the water, it is important to remove the parents from the breeding pond if you are not intending to rear the fry yourself. The eggs will be fertilized by the male koi and hatch in about 4 days. After hatching, the baby koi will feed on their yolk sac for another 3-4 days before they start to look for food. At this stage, it is important to start feeding them powdered koi food 4 times a day.

Eggs Do Koi Fish Lay

How Many Eggs Do Koi Fish Lay? 

During a koi fish breeding season, a 2-pound sexually mature koi can produce up to 100,000 eggs. A female koi's weight is used by professional koi breeders to estimate the number of eggs she produces. A female koi may lay 50,000 eggs for every 1 pound of body weight.

How Many Times a Year Do Koi Spawn? 

Koi fish usually mate once a year for approximately six to seven years after attaining sexual maturity. Some breeders are able to get pairs of koi to spawn twice each year, although the female koi will lay far fewer eggs the second time around.

What Month Do Koi Fish Breed? 

The length of the spring season, in other words, Photoperiod, is important for koi fish breeding. According to a popular Japanese idea, the moon causes female koi to lay eggs. In accordance with this thinking, Japanese koi fish breeders pick the female koi from the koi pond in January. Then they place the fish in the breeding tank for feeding.

If you're breeding indoors, be sure the area has a natural photoperiod. You may accomplish this by using timers that mimic the lengthening of the day. This method is useful in encouraging female koi to produce eggs. The chosen male may stay in the pond until the temperature rises a bit.

How Do I Know if My Koi Eggs Are Fertilized? 

Fertilized koi eggs are tiny round beads that are clear or very light brown with tiny dots on them. Non-fertilized koi egg whites will turn white and acquire a fuzzy appearance.

Should I Remove Koi Eggs from the Pond?

If you want to look after the eggs and fry, you must remove them from the main tank. If you do not remove the eggs, the adult Koi fish are likely to consume most or all of them. This is something that all fish, not just Koi, do. So you should gather the eggs as soon as possible after they are laid.

How Often Do Koi Fish Lay Eggs?

A female koi fish will deposit eggs every year, usually in the late spring (May or June). Spawning is generally induced by external stimuli such as Water temperature stays within the range of 65-70°F; Typical day length for late spring (approximately 12 hours);

What Is the Easiest Way to Breed Koi Fish?

Wait until late spring or early summer, when the water and weather are warm enough, to breed koi. Make sure there are at least 1 male and 1 female in the mating pond you're using. During the koi fish breeding season, look for white growths on the pectoral fins and heads of male koi. It indicates that the fish are ready to mate.

When you see this, place a receptive female in the pond with the male. The eggs will hatch within 3 to 7 days. Baby koi attach themselves to the pond's sidewalls once they hatch. After a few more days, they learn to swim. The koi fry survives on their own egg yolk during the first few days of their life. After that, they require your assistance for feedings.

You may also improve the chances of your koi fish breeding by providing them with nutritious food for the month leading up to the breeding. Feed your fish as much as they can eat in five minutes. Wholemeal bread, oranges, and whole lettuce are excellent nutritional sources. You should also provide your fish with a nesting area.

Is Breeding Koi Fish Profitable? 

If you're less sentimental, koi may be a viable alternative investment. But first, you must understand how to select them and care for them. A koi's worth is determined by its size, bloodline, honors, beauty, and breeder. Starting at $50 and rising to $300,000 or more.

Koi fish may be worth millions of dollars — the most expensive koi fish ever sold was valued at $1.8 million. Koi are a kind of carp that may be found all across the world. However, what distinguishes them is their coloring and lineage.

Final Thoughts 

Koi fish are a popular choice for aquariums and ponds. They come in a wide variety of colors and can be bred relatively easily. It's generally a good idea to breed koi fish, and it can be a lot of fun and rewarding.

Breeding koi fish is not as easy as it seems. There are a lot of things you need to take into account if you want to be successful at it. However, with the right information and dedication, it is possible to breed koi fish profitably. Do your research and make sure you are providing the best possible conditions for your fish, and you should be able to see positive results.

Sarah Robertson

I am a passionate blogger who also happens to be a fish keeping enthusiast. Writing about my hobby is something that I absolutely love to do, and it's no secret that my chosen topic is always centered around fish keeping.

Sarah Robertson

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