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Breeding Koi Fish

Breeding Koi and taking care of your Baby Koi can be an exciting process, watching nature at work, but it can be a hard job to do. Especially if you do not have a lot of time to watch your Koi. As you well know (if you already have Koi) they are full of surprises, and the same goes true for breeding Koi. Having given birth to a new generation, they would as willingly eat it as see it grow up. This attitude will continue until the baby Koi are maybe 3 in (8 cm) or larger in total length.

Correct nutrition makes a major contribution to the vitality and color of a fish, so supplement the normal diet of your Koi (while in the spawning tank) with good quality frozen foods, such as bloodworms and daphnia. Feeding these prepared foods will made up for any live foods that the fish are not eating wile they are in the spawing tank.

Breeding Tips

Koi keepers who are committed to breeding should take the following to heart:

  • Select Koi parents with the best attributes of their variety. Pretty Koi parents do not necessarily make pretty babies, so choose parent fish on the strength of their body shapes, good quality color, and good scalation rather than looks alone.

  • Do not use show quality koi for breeding; they will suffer bruises, cuts, torn fins, and missing scales, as well as stress during spawning.

  • Get both parent fish into prime health before spawning and again afterward.

  • Cull the fry. Few varieties breed true, and every poor specimen must be weeded out in order to strengthen, not weaken, the gene pool.

  • Don’t make errors. An entire breeding can be wiped out through carelessness and oversight.

  • Keep notes and records for future attempts. Above all, do not expect a breeding to produce multiple champions.

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Spawning Koi

Even after careful planning, male and female Koi will sometimes swim around enjoying the company and not do anything until days later, when suddenly you least expect it they will have exhausted all their passion and, by the time you find out they will have already dined at leisure on their own eggs.

After the initial risk-stage (3in in length) has passed then Koi are extremely friendly with their baby Koi and any other fishes and they will not harm them.

Koi fish picture

The female will send out pheromones (a scent) which will drive the males nuts and finish the maturity of its sperm and the male will then chase the female. They can be seen constantly nudging the female. It may look like one Koi is being bullied by another Koi. This is quite a brutal affair because unlike most fish the gravid female koi cannot lay eggs they have to be driven out of her by a male.

Fish will come into spawning condition at the end of June or the beginning of July, depending on the water temperature. Mating activity usually happens whenever the water heats up rapidly and is more apt to happen in the morning and evening hours.

Spawning (breeding Koi) will generally last only 20 to 30 minutes and can easily be missed. A good indicator that spawning has happened is to look for the presence of a froth or scum on the water’s surface.

Keep checking for translucent eggs, so they will not be eaten. Male Koi will be ready to breed when they are 2 years old, but females should be 3 years old. It is possible though that younger Koi will breed but their offspring will be of poor quality.

Eggs are spawn and sperm is milt.

The female is capable of carrying around 100,000 eggs for every 1kg of body weight. So a female of 10kg in weight will pass 1,000,000 eggs of which 60% will hatch.

Dependent on temperature, the egg will hatch in around 5/6 days but the poor little fry has not really had time to develop, but the longer it stayed in the egg the bigger the chance of being eaten, so mother nature again has equipped the newly emerged fry with only the bare essential but everything the fry needs to survive the next few days while further development takes place.

Koi will generally spawn just after or during an isolated warm spell as spawning time becomes imminent, you will notice the males chasing the females around the pond. This activity will get progressively more in earnest as the days go by and spawning gets closer.

Goldfish mate and produce young earlier than Koi. A Koi must be about 3 years old before he or she can produce offspring. Goldfish are the "hussies" of the pond and are always "going at it" no matter how old they are or what time of year it is. Koi, on the other hand, are more selective about the times and generally spawn only once or twice a year and it is during times of water temperature change or a heavy rain. It's not unusual for a group of Koi to spawn during a Koi show after being transported from their home pond and put into show tanks.

Spawning Tank

koi pond pictures

If you plan on Breeding Koi Carp you will need a spawning tank. A spawning tank can be any container that has dimensions of about 8x6 ft (2.4 x 1.8m) surface area and a depth of not less than 12in (30cm). Make sure and put a spawning medium for the eggs to fall into. This could be any hardy aquatic plants, bristle brushes, or you can purchase spawning mops from your local dealer. Branches of conifers (evergreen tree or shrub) are also used and Spanish moss is a favorite choice for many koi breeders.

The medium is used purely to give the eggs something to stick on. Cover about two-thirds of the tank with the medium. After the Koi fish are placed in the tank the male will chase the female and bump her rear end to encourage her to shed her eggs for the Koi breeding to take place.

The male will then release his sperm (known as Milt) it contains millions of sperm, only one sperm can enter one egg. This will normally happen in the early morning.

Try to avoid disturbing the Koi before and during spawning, keep a careful eye on them, as the males may bully some females. If this happens, remove the female and place her in a separate pond.

When they have finished spawning, the females hang head down, respiring heavily, and the other fish will become less excited. Gently remove the spawning medium and carefully place them in a vat for incubation.

Baby Koi

For the next 3-4 weeks they should be fed liquid or powdered fry food.

It is very important that the rearing tank be clean as well oxygenated. After one month from hatching you may feed your baby Koi. How often do you feed baby Koi you may ask? The answer is frequently. Egg yolk is favored by many breeders. The main thing when feeding your fry is that the food be small, of high protein content and is fed many times a day. Remember, make sure and keep the water as clean as possible. Koi fry at the 'swim up' stage do not have any developed taste buds and so must detect their food by sight. Therefore they need to have food all around them.

Hard-boiled egg yolk is an ideal food for the first day or so - this has very little dietary value, but will increase the size of the stomach. Newly hatched brine shrimp (Artemia sauna) larvae are also a good food source for young Koi fry. Start feeding the brine shrimp when the Koi are about one week old. After another week or so, the baby Koi will be ready for a mash diet(the powder dust that is left after the manufacturing process of fish food). From this time onwards, feed the koi food of a size that can be taken by the smallest fish in the vat.

You will need to remove accumulated debris and waste frequently during this first feeding stage. A siphon made from aeration tubing is ideal for removing settled and suspended waste from the incubator, and an old toothbrush is useful to clean the outlet screen. You should also add fresh water regularly to the vat to remove nitrates and ammonia. Tap water which contains high concentrations of chlorine, should be aerated before it is added to the vat, to allow the chlorine to evaporate. After three or four weeks, the baby Koi will have grown to 5-l0mm(0.2-0.4in) in length and will be starting to take larger quantities of more generously sized foods.

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If you are not concerned about breeding your Koi, or in their quality, you can simply leave all of your Koi together. Most of the baby Koi will be eaten by the Koi or other pond predators, so only a few lucky ones will survive. Usually only the toughest and worst looking will survive. The badly colored has an advantage because they are less easily spotted (by predators or other Koi) then the good ones.

A female Koi may shed up to 400,000 eggs during spawning but there will be heavy natural losses due to failure to be fertilized, bacterial attack, embryonic problems causing death before hatching. There are a few thousand fry that will survive. A lot of these will be poorly colored, or deformed, or badly shaped. Koi breeding involves a lot of culling, not a pleasant thought but in the wild nature is not generous either and most of the baby Koi would perish which is why Koi shed so many eggs.

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Foods for baby Koi fall into three categories:

  • Commercial foods: Those specifically created for baby fish, (such as liquid fry food) or foods for larger fish (such as blended freeze-dried krill) that you modify to be acceptable to baby Koi.
  • Live foods: Food such as baby brine shrimp that can be hatched from commercially available eggs.
  • Foods from your refrigerator: Foods that are part of a human diet such as hard boiled eggs.

Here is a table of foods to meet the fry's nutritional requirements:

Baby Koi Foods to Have on Hand

Food Amount
Liquid fry feeder four dozen tubes
Brine shrimp eggs for
hatching live brine shrimp
15 oz.can
Frozen baby brine shrimp 1.75 oz.
Powdered fry food for egg layers 50-lb. bag
Hard boiled eggs cook a dozen and use as needed
Fish flake food 1lb.
Freeze dried krill,
powdered in your blender
16-oz bag
Frozen daphia cubes 16-oz package
Standard Koi food,
powdered in your blender
5 lbs.
Baby-Koi sinking pellets 5 lbs.

Breeding Koi Beginning

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