Koi Breeding Methods

trickydicky · 11-02-2011, 12:50 PM

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 environment 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, especially 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 together, 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 the 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 synthetic 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.
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.
3. Actual Spawning. The pregnant female shows her readiness to spawn by exhibiting movements that seem to indicate an intention to arrange the spawning material into a nest. The male is attracted to these movements, and tries to force the female against the wall of the pond. If there are two males in the pond, they will attempt to sandwich the female between them.

The thrashing and bumping of the males against the pregnant female causes the latter to release her thousands of eggs into the spawning material (and into other places as well). The eggs are very sticky and will adhere to anything they come in contact with. Simultaneously, the males will release their sperms onto the eggs to fertilize them. A second cycle of the same ritual may be employed if the female still needs to discharge some eggs.

This spawning activity can be very physical, or even violent. Injuries to the female may happen, especially if the male koi continues to beat her up. The male should be promptly but very carefully removed from the pond if this happens. It would be good to leave the female in the pond to let her recover her strength. Keep her safe by keeping her properly aerated and preventing her from jumping out of the pond (some females have been observed to be jumpy after spawning.

4. Isolation and Incubation of the Eggs. The eggs, being small and immobile, are vulnerable to predation not only by its parents but by pond wildlife as well. Thus, it is necessary to secure the eggs from predators. If you used spawning ropes as spawning material, you can easily lift these from the spawning pond and transfer them to a hatchery (which can just be a vat or tank) where the eggs can incubate safely. If you don't have a separate hatchery and intend to let the eggs hatch in the spawning pond itself, you should transfer the female carefully to another pond.

The hatchery (if one is used) where the eggs will be transferred and allowed to hatch must be of the same temperature as the spawning pond. It must also be aerated very well with no water disturbance. Filtration of the hatchery is not required, but adequate oxygenation is certainly a 'must'.

5. Rearing of the Larvae. Most of the eggs usually hatch 4 to 5 days after they are laid. By the 6th day all of the fertile eggs should have hatched. The newly hatched larvae will look like a huge army of jerking 'commas'. The main challenge in rearing the newly hatched larvae is feeding, which can pollute the water as wastes build up especially since filtration should not be done at this point. The larvae will survive on their egg sacs for the first 24 hours. After that, the larvae must be fed 5 times a day. Do not give dry food to the larvae to prevent water pollution. Instead, give them live natural foods such as daphnia and infusoria. The growth of green algae will also help augment the natural food supply. After a few days the larvae may be transferred very carefully to a larger growing-out pond where they should continue to receive live food until 6 weeks of age.

markf1fan · 11-02-2011, 03:31 PM

very good reading and interesting as you know i would love mine to spawn this year lol. one thing it does not tell you is at what temp do they spawn at. mark

trickydicky · 11-02-2011, 03:40 PM

My god Mark do you want to artificially inseminate them too

18c - 20c is an good temp however barometric pressure can have an effect too ie thunder
And 20c being a far better temp

markf1fan · 11-02-2011, 03:43 PM

omg that will take months for my pond to hit 18c lol. best get my heater on and running then lol

ogawa only · 11-02-2011, 05:20 PM

i'l confuse you now , females are usualy ready when they've had a 1000 degree days

trickydicky · 11-02-2011, 05:28 PM

Just Like The Wife :d

keithatrax · 11-02-2011, 06:19 PM

Quote:

Originally Posted by ogawa only

i'l confuse you now , females are usualy ready when they've had a 1000 degree days

so am i right in thinking thats about 50days at 20c?

markf1fan · 11-02-2011, 06:23 PM

Quote:

Originally Posted by ogawa only

i'l confuse you now , females are usualy ready when they've had a 1000 degree days

now i am confused lol, 1000 degree days from when.

amphibian · 11-02-2011, 06:46 PM

Quote:

Originally Posted by keithatrax

so am i right in thinking thats about 50days at 20c?

adds up right, although the pallington carp would disagree and breed when you turn up for a week session or on 21st may, they seemed to love that day

keithatrax · 11-02-2011, 06:50 PM

Quote:

Originally Posted by markf1fan

now i am confused lol, 1000 degree days from when.

The idea is to cool down the fish for about 4 weeks at around 10 degrees C. Then, the fish are warmed to 15 degrees C and held there until 1000 degree days are done. That would be 67 days with good feeding to enrich the eggs.
The fish could also be slowly warmed up to 20 degrees C over several weeks to reduce the number of days