Baby koi fry food

I’ve got koi fry –now what!? A step wise approach to raising baby koi

by Koi-Care staff

If you just noticed that your pond now has a million little koi fry swimming around then skip down to the feeding section but if you haven’t bred koi yet and need an introduction then read on. Spawning typically occurs in the early summer months and is very water temperature dependent – 68 degrees F is the minimum for spawning. 

Your adult koi will have to be sexually mature to engage in successful mating and this typically occurs at age 2 for males and at age 3 for females.  Keep in mind when you are selecting the parents that the larger the female, the more eggs she can produce.  

If you are wondering about how to tell the sex of your koi, there are different approaches to this such as looking at pectoral fin shape and size but the tried and true method is to inspect the underside of your koi.  If there is one vent (slit) then you have a male, if you have two vents (slits) then you have a female.

Usually spawning activity, and the behaviors associated with it, will take place in the early morning and may only last 30 minutes.  The whole process is a bit rough as the male needs to physically stimulate the eggs to be released by nudging the female’s belly.  After eggs are released, the male fertilizes them by releasing sperm.

Here’s a short video to give an idea of what spawning behaviors actually look like.

Breeding Material

If you plan on having a dedicated spawning tank you will most certainly want breeding material.  This is simply material that offers surface area for the eggs to stick to.  This could take the shape of aquatic plants, ropes, a “spawning brush” or a “spawning mop”. 

Most importantly it needs to be something that won’t be toxic in any way and has lots of surface area for eggs to attach.  You will want to have plenty of breeding material for the eggs to attach to-maybe around 50 to 60 percent of the bottom of the spawning tank should be covered.  

The size of your spawning tank will depend on how many fish you plan on trying to get to reproduce.  It should be something on the order of 1 to 2 feet deep and maybe 6 feet by 6 feet –some hobbyists have used inflatable kiddie pools with success. After eggs have been laid and adults removed from spawning tank you should see hatching around 4 days later. 

When you are satisfied with the density of hatched fish you can remove the breeding material.  So what will the eggs look like? See below.

Thanks to Anthony R. for submitting these pis of his koi’s eggs

Tank/Pond Conditions

You may choose not to go with a separate fry tank or pond and simply let it happen in the main pond.  If this is the case be aware that if you have goldfish amongst your adult koi you will have some egg loss due to the goldfish’s appetite for koi eggs. 

Your koi eggs will hatch around 4 days after they are fertilized.  They will then attach themselves to structure like the side of the tank or pond for 2-3 days where they will be feeding off their yolk sac. If you are seeing a great deal of swimming koi fry and also a lot of eggs at the bottom feel free to remove those as they most likely failed to fertilize and will only drive ammonia levels up.  Be sure to monitor all your water chemistry, especially ammonia and pH.

What to feed your koi fry?

At around the 10th day (sooner depending on water temp) you will notice your koi fry trying out their new-found ability to swim and it’s at that time that feeding should begin.  A lot of koi enthusiasts will start off with something called “infusoria” which is not a thing but more of a size classification. 

Generally, it’s defined as very small aquatic organisms and for koi fry those should be live daphnia (water fleas) and/or brine shrimp (“sea monkies”).  If you can’t obtain infusoria you can try chicken eggs. Boil the eggs (some just use the yolks) and, in a blender, mix with about 30 or so ounces of water from the tank or pond. 

Simply squirt that mixture over the surface of your breeding tank or pond.   You will want to feed around 4 times per day.  In general you are trying to match the size of the food with the koi fry such that it is an appropriate size for them to eat. After about a week of this mixture you can switch to a powder called “fry powder” which can be sprinkled over the water’s surface. 

You can also use standard protein infused koi pellets and basically grind them up into a fine powder and select for a certain grain size by shaking it through a sieve.  It may take a few days for the fry to associate the new powder with food and acquire a taste for it. Be sure to clean the bottom of the tank for any waste and excess/uneaten food –you really want to avoid ammonia build up.

Make sure that you provide plenty of aeration for your koi fry and this is especially true in the summer when warmer water temps mean less oxygen carrying capacity of water. Some other foods that you can feed are frozen brine shrimp, growing live brine shimp in your containment tank or main pond and freeze-dried krill. You may also add, as a nutritional supplement, spirulina powder and wheat germ.


One mistake people make is trying to keep all the koi fry, that’s a bad idea. You definitely want to “thin out the herd” because by doing so you create a more healthy environment for the remaining koi. Your first round of culling should take place at around 1 inch or 25mm.

This should fall at about 4 weeks (possibly longer) after swimming is first observed. Another culling should take place a month after the first or about when they are about 2.5 inches or 6.25cm. The first and second culling should remove about 80% of the initial population.

Additionally, a third culling should start a month after the second one and remove 50 to 60% of what’s left (see the “Breeding Timeline” below). When culling you should be looking for deformities, undesirable coloration, erratic swimming, sluggish swimmers and generally undesirable traits. You don’t necessarily have to euthanize these fish-give some to your friends!

Final thoughts

When your koi do finally make it to a larger size and you want to introduce them to the main pond be aware that adult koi will eat most anything and the baby koi might be on the menu if they are small enough. Be sure to release them only when they are big enough that they won’t actually fit in the adults mouths!Typical Timeline for Koi Fry

A Fry Guide — Koi Story

Jun 13

Baby Koi: A Fry Guide

Kenneth Koi

Everyone knows koi fish for their underwater beauty. But not everyone knows the effort that goes into raising them. From a baby koi to a full grown one, these fish can take a lot of hard work. However, hard work yields results – in beautiful koi, that is!

If you’re looking to raise koi, consider purchasing young ones. They cost less and you even get to watch them develop coloring, shape, and size. However, there are several things you must keep in mind when raising young koi.

Young koi enjoying a swim in the sunlight.

  • Natural Waterscapes Pond Remedy | Helps improve water conditions for koi fish.

  • Flexzion Pond Pump | Cleanly filter pond water at set speed to ensure best water quality for growing koi fish.


When koi eggs are fertilized, they cling to pond plants for three to four days. Once they hatch, they sink to the bottom of the pond. These baby koi are called koi fry. Once released from their yolk sacks, the baby koi take cover in pond plants.

Baby koi do not typically need to be fed in the first few days. They live off of their yolk sacks and small organisms found in pond water. However, if the koi fry are hatched outside of a pond setting, they will require specialized feeding.

After a baby koi develops and begins swimming to the surface, it is ready to feed. These young koi require different food  than their fully grown friends. One thing to keep in mind is their mouth size. These koi are very small, and their mouths even smaller! In the first month of life, liquid food and very small suspended-particle food are good choices. Feed your young koi four times a day.

Baby koi fish need smaller sized food for their small mouths.

During feeding times, keep a close watch to avoid over and underfeeding. If food is still visible after koi are done eating, you are overfeeding your fish. The leftover food will harm the water. If you are underfeeding your koi, watch for frequent weak or deceased fish.

A koi fish will produce thousands of eggs when spawning. However, it’s not feasible for an owner to house and care for so many fish. A number of your koi will be eliminated naturally. Sometimes larger koi will eat smaller ones. Size and growth vary from species to species, so be aware of what koi are growing up together in the pond. Goldfish, which are many times raised with koi, are also known to dine on koi eggs and fry.

Sometimes larger koi will eat smaller koi.

While some koi are eliminated naturally, koi owners use a process called culling to keep numbers of koi fish down to appropriate levels. Culling is the selective process that removes some fish from the koi pond. These removed koi are usually euthanized. While culling may seem cruel, it is important to remember that it is essential to the health of the koi in the pond. Overcrowding is harmful to both your koi and your pond. Culling will ensure the health and wellbeing of the koi in a safe way.

Culling is recommended once a month for the first three months. At the first and second culling, remove 80% of the baby koi. In the third month, remove 65%. While this seems like a lot, it is only reducing your numbers down to a manageable level. When culling, pull out koi that show signs of weakness or aggressiveness. Also remove any koi with signs of deformities, which are common and especially evident in their spines, fins, and tails. The Australian Koi Association  website has more information on this.  

Raising koi can be really demanding, especially throughout the early stages. But watching baby koi grow into full grown fish is the ultimate koi keeper’s reward! Navigating those early months can be a time of adjustment, but with these tips we’re sure you’ll do just fine! Do you have any advice for raising baby koi? Write us a comment or contact us via the contact form.


Kenneth Koi

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Kenneth Koi

A Guide to Koi Fish Aquariums

What Koi Fish Eat: Keeping Your Koi Healthy

Koi carps (care, feeding, breeding, types, compatibility)

Koi carps are a "work" of Japanese ichthyologists-breeders. On the basis of ordinary carp, dozens of species of koi carp were bred, striking everyone with their unusual and bright coloring.
Such fish (koi) can be conditionally classified as aquarium fish, as their size can make them difficult to keep, at least in a home aquarium. Let's say more, such fish can be an ornament in any institution. For example, they can be seen in the pool of the hall, or in the artificial river of the zoo. nine0005 In any case, koi carps will please you with their appearance and bring positive emotions into your life. Learn more about these fish below.

The history of the appearance of koi

The time of the appearance of koi in Japan is not known for certain. Some sources say that already 2500 years ago carps lived in the rivers and lakes of the Japanese islands, other sources claim that they were brought to Japan by Chinese conquerors in the 14th-15th centuries AD. One thing is clear, that carp often served as the only food of the peasants. Then they began to grow them artificially in rice paddies. Sometimes individuals with an unusual coloration grew up among carps. They were not eaten, but left for further reproduction. By crossing fish with different colors, even more interesting color combinations were obtained. The first colored koi show was held at 1914 year.

Koi varieties

There are a total of 80 koi carp species, divided into sixteen groups with certain similar characteristics. They are:
1. Utsurimono,
2. Showa Sanshoku,
3. Taisho Sanshoku,
4. Kohaku,
5. Tantyo,
6. Asagi,
7. Bekko,
8.90 Kawari Ogon, 90 10. Hikari-moyomono,
11. Koromo,
12. Kinginrin,
13. Shusui,
14. Goshiki,
15. Doitsu-goi,
16. Kumonryu.

According to Japanese canons, a fish that has passed 6 breeding selections can become a koi carp. As you can see, everything is very strict. In order for an ordinary fish to become a koi carp, the shape of the body, fins, their relationship to each other, the pattern and color of the spots, and such a speculative concept as the posture of the fish are evaluated. Carp live up to 30 years, reaching a length of 50 cm to 90 cm.

Keeping koi

Since koi fish are quite large, they are kept either in large aquariums, but more often in garden ponds. Moreover, it can be kept all year round, protecting the pond from snow and frost. Water parameters for keeping koi:
- water temperature from 15 to 30 degrees. Although they can tolerate temperatures from 2 to 35 degrees Celsius;
- acidity of water pH = 7 - 7.5;
- oxygen content 4-5 mg/l;
- water hardness 4-10 units.

Koi feeding

What rules should be followed when feeding carp:
- food should be eaten in 10-15 minutes;
- feed must not contaminate water;
- the portion of food should be small, it is better to underfeed than to overfeed;
- feed 2-3 times a day. nine0003

Carp fry are fed with infusoria, daphnia, wheat yeast, spirulina. Then they begin to include dry food in small fractions in the diet, the size of which increases with the growth of the fish.
Adult carps are omnivorous, so the diet can be varied - dry pellets, soaked bread, fruits, vegetables, boiled shrimp, live food without pathogens.
Very often natural and artificial foods contain dyes. It is necessary to ensure that there are not too many of them, otherwise it can lead to liver disease. nine0003

Koi breeding

A spawning pond is used for breeding, where two or three males and one female are planted. After spawning, spawners can be returned to the main pond, since carp can eat not only eggs, but also fry.
After a few days, fry appear from the eggs. They have a special adhesive pad with which they stick to any surface and hang there. At this time, they do not need to be fed. As soon as the fry begin to swim, they begin to feed them. nine0003

Compatibility of koi with other fish

Since koi are very large fish, they are most often kept in aquariums or ponds alone, as they can eat small fish.

Koi varieties

Asagi. Scaled carp with a net pattern on a dark blue background.

Fins and belly usually red.
Bekko. White, red, yellow, with a black spotted pattern, which in no case should go over the head, otherwise it will be a different kind of koi. nine0003

Deutsu. Scaleless carp crossed with German carp, hence the name.

Kawarimono. This species includes all non-metallic koi.

Kinginrin. This word means "golden silver scales". The scales of these carps have a shimmering effect of gold or silver.

Koromo. The peculiarity of these carps is that a pattern of a different color is superimposed on a red pattern.

Kohaku. White koi with red pattern. One of the most famous koi breeds. nine0003

Fire. Single color carp. Often there are red, yellow, orange colors.

Tancho. This type of koi is named after Japan's national bird, the tancho crane. Like a bird, a carp has a red crown on its head.

Hikarimuji. Monochromatic koi with a metallic effect.

Seam. Carps with a red and white pattern on a black background.

I think the presented photos of koi carp will not let you doubt that such fish will decorate any place. It doesn't matter if it's a decent-sized aquarium or some other body of water. nine0003

What to feed Japanese carp, what food to choose for koi

Koi carp or Japanese carp is a fish of amazing beauty, which has a bright color, medium size and high resistance to external influences. In the Far East, these fish were launched into homestead fish ponds and their motley movements were observed. Today, koi are very popular in fish farms and master ponds. Koi food is of particular importance. Therefore, it is important to know what to feed them, since it is the balance of nutrients that allows the inhabitants of the lakes to have a bright and saturated color of the scales. nine0003

Feed types

Multi-colored carps are omnivorous, in their natural pond habitat they can perfectly eat both food of natural origin and dry food intended for a particular breed of fish. More often, the owners of Japanese carp prefer to save time and energy by choosing industrial feed for the inhabitants of the ponds. Purchased food has many varieties in terms of composition and nutritional value - this allows you to achieve various goals in the process of feeding both fry and adults. nine0003

During the period of cold weather, it is required to select special formulations for cold water - their basis is vegetable protein. It is believed that the digestive system of fish copes better with amino acids of plant origin. Feed amino acids are obtained from wheat germ, as the most nutritious part of the cereal. Japanese carp food also contains some animal proteins.

These compositions are 40% composed of proteins - this is the most important component that provides all the vital functions and health of the fish. Winter food for koi carp is rich in vitamin E, which forms a mottled reddish color of the scales. The complex of mineral substances and unsaturated fatty acids increases the digestibility of granules. Probiotics allow to maintain the normal microflora of the digestive tract and maintain a high level of immune defense of the Japanese carp. nine0003

After wintering, koi carp is weakened, its immunity is reduced, the fish is prone to various diseases that affect not only the scales, but also the internal organs. Therefore, when the water temperature rises, colored fish can be fed with special mixtures and floating granules with a high content of probiotics. These component foods are high in polysaccharides, nutrients essential for the growth of intestinal bacteria.

A specific type of food helps to increase the barrier properties of the fish organism. This koi food has a low protein content (less than 30%), which allows it to be fed to fish with a formulation suitable for cold water feeding. It is necessary to mix such types of feed into the diet of lake inhabitants only after the environment has warmed up to 10 degrees. nine0003

After the water temperature in the reservoir reaches a value of 12 degrees, the stronger koi can be transferred to one of the basic feeds. These are universal products, in their composition the percentage of protein content is increased and the amount of fat is reduced (no more than 3%). The use of lipid-reduced koi food is recommended until the water temperature rises to 15-20 degrees.

After the water has warmed up enough and the koi have adapted to the changed conditions, it is necessary to introduce premium food into the diet of the fish for active growth. This product is characterized by a high content of amino acids and fats, which allows the inhabitants of the underwater world to actively grow and gain weight. It is possible to combine the basic food with special fortified formulations rich in tocopherol, which will help maintain the natural bright colors of pets. nine0003

As for specific products, the market is filled with different types of feeds that allow you to achieve the desired results, each manufacturer offers to buy dry food for all fish breeds. Consider the most popular companies that produce a quality product:

  • Coppens Koi. The manufacturer offers a whole series of products for this type of fish. The line includes positions for nutrition at low temperatures, with spirulina (to enhance color), for health promotion, basic nutrition, for the growth of young individuals, etc. A complete standard diet (for an ambient temperature of 15 degrees) ensures rapid growth, beautiful color, helps to avoid obesity, which is especially important for exhibition pets. In addition to protein, fats, fiber, ash, phosphorus and vitamins, the composition includes the probiotic inulin, which ensures healthy digestion of fish, as well as the carotenoid astaxanthin, which enhances the bright pigment of carp; nine0003

  • Yamato. The manufacturer offers food options for the autumn-winter period, for low temperatures, for the main food, for the rapid growth of young individuals. Belongs to the premium class, the composition of the standard mixture for carps includes proteins, fats, fiber, phosphates, calcium, vitamins A, D3, E, ascorbic acid;

  • TetraPond is a food in the form of sticks, flakes and pellets for koi of different sizes. In addition to the content of all useful components important for the inhabitant of the pond, the composition stimulates the strengthening of immunity and is easily absorbed in the digestive system, minimally polluting the water; nine0003

  • Tetra. The food is sold in packaging depending on the age of the fish: 150 grams for fry, 1 kg for pets up to 10 cm, 2.5 kg - the main food for adult fish from 10 cm and from 20 cm in the form of floating granules.

How to prepare your own feed

As noted, the koi is an omnivorous fish that tolerates both animal and vegetable food well. For this reason, you can save money, and instead of purchasing expensive industrial feeds, prepare an equally high-quality mixture with your own hands. This method of feeding will be more environmentally friendly than the option with a purchased composition. nine0003

Almost everything that can be found in nature can become components for the preparation of complete homemade food. Koi are not picky eaters and are excellent eaters of the following organisms:

  • bloodworm;

  • tubifex;

  • daphnia;

  • coretra. nine0003

Earthworms are a good option for feeding every day. It must be remembered that before sending them to the “table”, the worms need to be kept in clean water for some time in order to cleanse their intestines.

Japanese carp eats well cereals that need to be brewed in boiling water without adding salt. It can be buckwheat, millet or semolina. Rinse the boiled porridge well under water so that it becomes crumbly and excess gluten is gone. The paste does not come out of the intestines of the koi and clogs it, which can lead to the death of the fish. nine0003

Soft aquatic plants can be included in homemade food, for example:

  • duckweed;

  • riccia;

  • vallisneria;

  • wolfium;

  • hornwort, etc.

For harvesting feed, you can use almost any greens and vegetables that need to be scalded with boiling water, and then cut into small strips. Lettuce, parsley, dill, dandelions, plantain can be used as raw materials. Similarly, you can use zucchini, carrots, cucumbers and pumpkins - these products are rubbed on a fine grater, and then sent to feed the inhabitants of ornamental ponds. nine0003

How to properly feed pond fish

Koi carp, despite its high resistance to external conditions, requires special attention. This is especially true of the feeding process, in which it is necessary to take into account both the physiology of a particular breed and the general principles of feeding lake fish.

When feeding fish with dry food, it is important to take into account that granules, like flakes, swell in water. For this reason, portions dispensed should be small. Carps willingly eat everything they are given, and then the food in their stomach increases significantly. This can lead to increased gas formation, constipation, inflammation of the digestive organs, and even death of pets. nine0003

Before feeding, you need to put food in water so that it swells a little. For flakes, 10-15 seconds is enough, and for granules - 30 seconds. Only after that dry food is lowered into the pond. As for the frequency of feeding, it depends on a number of factors, such as water temperature and the age of the koi. There is a rule: the colder the water in the reservoir, the less food the fish need.

Young fish are fed hourly, and the amount of food can be up to 10% of the body weight of each individual. More adult carps are treated 2-3 times a day, sending food to the reservoir in the amount of 3% of the weight of the fish in it. The rest of the feeding process and food volumes are adjusted to the individual needs of the pets. If after feeding the carps in the pond are still asking for food, then they can be given supplements, and if the pellets remain on the surface, then the feeding procedure should be completed. nine0003

There is an important rule: it is better to leave Japanese carps a little hungry than to overfeed them. Oversaturation with food leads not only to a deterioration in the well-being of pets, but also to a disruption in the performance of cleaning systems.

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