From: Andreas.LAGGIS@DG8.cec.be
To: AQUA-L@LISTSERV.ifmt.nf.ca
BREEDING KOI: PRACTICAL TIPS
Breeding koi is the same as breeding common carp.
1. One month before the start of reproduction season of common carps in your area, you have to separate males from females. Sexing of spawners can be easily done 2-3 months before reproduction season;
2. When the water temperature is constantly above 18 Centigrade (for temperate areas) you transfer the two sexes in the same water tank (2 males with 1 female, or approximately in equal weight proportions). The recommended fish stocking density is 1 fish/sqm. Simultaneously we introduce in the spawning tank, floating aquatic-plant collectors or collectors from other appropriate materials as a nest for the collection of sticking eggs. Flowing water in the spawning tank would be also required. Continue feeding;
3. Make the above transfer preferably in the morning and avoid injuries and stressing the fish. Within 1-3 days, but generally the next day early in the morning, all kois will spawn. One kg of females produces a variable number of eggs, but generally between 100-200,000. Collectors of eggs have to be replaced and transferred to the hatching tank (see below) every 1-2 hours during spawning;
4. Hatching of collected eggs has to be done in another tank, with clean and running water, away from genitors, or in the "open air" in an appropriate, constantly humidified (by fine spraying of clean water) environment. This latter method would not get any fungi (Saprolegnia) problems. Hatching of eggs will take place within 2-6 days between 30 to 15 C, respectively, or 75-85 day-degrees accumulated temperature. Best WT for hatching ratio and survival
of larvae is achieved at around 20 C, but constant. Hatching ratio varies between 30 and 80%;
5. Just before hatching transfer the collectors (with the eggs still
attached to them) to the water of the fry rearing bassin. The hatched larvae have to be kept in this bassin for at least 10 days and up to 30 days. Feeding the larvae is another long story, that you must discover yourself, reading appropriate texts.
Andreas Laggis
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