Koi Breeding

This is in response to the request of my friend in Australia named Constantino asking for the technical details in growing Koi or Japanese Carps. I have been in this business for quite sometimes that's why I am able to answer all the matter concerns. I hope this will answer your inquiry.

BREEDING YOUR KOI


Basic Considerations in Koi Breeding

When starting a koi breeding or koi propagation program, several aspects must be carefully taken into consideration by the prospective koi breeder (note that in this article, the term 'breeder' may refer to either the person breeding the koi or the koi being bred). Some of these important considerations are discussed below.

1. The Brood Stock. The term 'brood stock' refers to the group of koi that is used for breeding and propagating new koi. It goes without saying that proper selection of the brood stock is very important for the success of any koi breeding program. All koi spawners must be healthy and sexually mature, i.e., they should at least be 2 years old. They must have absolutely no genetic deformities and must possess all the good qualities of excellent koi - perfect body conformation, excellent color quality, balanced pattern distribution, graceful movement, etc.

Koi are prolific breeders, with a single female capable of producing hundreds of thousands of eggs. As such, a breeding program doesn't need a brood stock of enormous size to produce sufficient quantities of fry. It is therefore logical to put emphasis on the quality of the breeders rather than the quantity. The only problem with having limited brood stock is the possibility of genetic inbreeding, so care must be taken to avoid this situation.

The size of brood stock required for breeding depends on the goal of the program. A hobbyist can get what he or she needs simply by pairing two nice koi, while a commercial koi farm that needs to produce millions of saleable fish must have around 100 females and about the same number of males.

2. Propagation. Many of us experienced seeing their first koi fry swimming in the main pond itself. Indeed putting a bunch of healthy male and female koi in a pond with good-quality water and some plants can lead to koi spawning and, consequently, the arrival of baby koi. This is not a good way to propagate koi though. Fry almost never survive in such an environment because they become dinner for their elders first. Fortunately, koi experts have already come up with other ways to propagate koi more efficiently.

Many hobbyists mimic natural koi reproduction under a more controlled environment, following these basic steps: 1) selection of the female and male (2 males may be used but not more than this) for the breeding; 2) preparation of the spawning area including the installation of adequate spawning materials; 3) 'conditioning' of the spawners prior to breeding; 4) introduction of the 'ready' male to the 'ready' female; 5) monitoring of the spawning until the eggs are released onto the spawning material and fertilized by the male; 6) removal of the breeders (or the eggs) from the spawning pond; and 7) adjustment of the pond parameters (e.g., aeration) to achieve successful incubation and nursing of the fry. See also: Basic Koi Breeding Method.

Many advanced koi breeders, however, now employ what is known as the dry fertilization method, wherein a tranquilized ripe female is manually stripped of her eggs, which are collected in a clean, dry bowl. This is done by gently squeezing her belly under dry conditions. The sperms of a koi male are then collected in a beaker by similar methods. The milt in the beaker is then poured into the bowl of eggs so that the sperms can fertilize the eggs. The fertilized eggs are then deposited onto the spawning material in the incubation pond.

3. Egg Incubation. At this point, the fertilized eggs of your prized koi breeders must already be attached to the spawning material, whether this is immersed in an outdoor spawning pond or in an indoor incubator or hatchery. Regardless of egg incubation environment, the water quality must be monitored and maintained at optimum levels at all times. Experts recommend a water temperature of 22 to 25 deg C during incubation. Adequate aeration must be provided but it should not disturb the water. And of course, as any koi hobbyist knows, the water must be clean. Some breeders don't provide filtration during incubation so as not to agitate the water.

4. Nursing of the Fry. Once hatched, the fry are liberated from their confinement, but become exposed to the harsh realities of the outside world. If they are in a well-planned koi fry nursery when they hatch, then they are lucky enough not having to worry about being eaten by predators (mainly their parents). Newly-hatched fry can't swim well, so water turbulence must be kept as low as possible without sacrificing aeration and filtration requirements. The larvae must likewise be provided with high levels of illumination since they are dependent at this point on vision to catch their food. Food supply must also be ample once the fry have hatched. The fry may survive on microscopic organisms in a mature pond. In an indoor hatchery, live food such as Artemia (brine shrimp) nauplii may be used.

Although more and more koi hobbyists are trying to breed koi using the dry fertilization method (thanks in part to the proliferation of YouTube videos showing how to do it), many prospective koi breeders still prefer the classic method of letting pre-selected koi spawn naturally in a pond. The reason for this perhaps is the simplicity of the classic procedure, which consists mainly of preparing the spawning environmen

t and letting the koi do what comes naturally for them. The steps involved in this basic koi breeding method are presented below.

1. Selection of the Parents. Choosing the right parents for your baby koi need not be difficult, but it can sometimes be tricky too. First things first - you need to know which of your koi are female and which are male. Female koi are visibly rounder than male koi, e

specially those that are ready to lay

eggs. Males are slimmer in appearance, and may develop roughness on their gill plates when ready to spawn.

Choose mature koi only for breeding, i.e., they should at least be two years old (younger koi will produce weak offsprings). Experts say that the optimum breeding age is 2-4 years old. Choose only healthy koi with no deformities whatsoever. Both parents should exhibit excellent body conformation and high-quality colors and markings.

Select the parents based on what baby koi you're after. For example, if you want Kohaku fry, then you need both parents to be Kohaku. Some varieties don't result in nice koi when bred togeth

er, so be sure to do a little research on koi variety pairing before doing it (unless you're after the excitement of uncertainty).

Some breeders use two males for a single female during breeding to maximize the yield of the propagation. The breeding act of the koi is very physical and can harm the participants (especially the female if the males are very aggressive), so this ratio of 2:1 must not be exceeded. One advantage of using just a single male is the higher predictability of what the offspring will look like.

2. Preparation of the Spawning Environment. Once the prospective parents have been identified, they need to be taken out of the main pond and isolated in separate and smaller ponds where they can be conditioned for spawning. Males are separated from females to prevent indiscriminate spawning. Many hobbyists start this isolation at least 1 month before the anticipated spawning date.

Eventually the female becomes rounder and noticeably bloated with eggs. Now with a heavy but soft abdomen, she is presumed to be ready to lay eggs and is very carefully moved to the spawning pond. This pregnant koi must always be supported by water during the move, even while inside a net. At this point the male is also assumed to be ready to participate in the reproduction as well, and is moved into the spawning pond a few hours after the female has already been acclimatized to it. Many breeders introduce the male in the evening, since spawning usually happens in the wee hours of t

he morning.

The spawning pond shouldn't be big - usually with an area of just 6 to 12 sq. meters. It should be thoroughly cleaned and filled with un-chlorinated water to a depth of about 50 centimeters. The spawning pond must have a generous amount of spawning material to encourage the female to lay her eggs on them. Many modern koi hobbyists prefer syntheti

c spawning ropes (see Figure 1) as spawning material because these are free of parasites, do not easily get damaged, and allow easy handling of the eggs, unlike spawning media of the natural kind. The easy-to-handle feature is important if you plan to move the eggs away from the parents right after spawning is completed. Many old-school breeders still prefer natural spawning material though.

Figure 1. A curled spawning rope (left) and a close-up of the spawning rope bristles (right).

The spawning pond must also be sufficiently aerated at all times. Strong but silent air pumps must be used. Unlike the main pond, aeration of a spawning pond must not result in water turbulence, since water tranquility is needed during spawning. As such, the aeration system of the spawning pond must be designed well to meet the aeration requirements without disturbing the water.