Key Points of Fry Selection Techniques in Koi Breeding

When koi fry have grown to a certain stage, they must be selected from the batch population. To do the selection work well, the area of the koi fry pond should preferably be about 2000 sq m (3.0 mu); because the selection work is done in midsummer, it should be carried out in the morning, and must be completed before 10:00 AM at the latest, otherwise unexpected damage may be caused by rising water temperature. On the day before seining and selection operations, the pond should be drained to lower the water level.

Showa Sanshoku can be selected from the “black fry” (body length about 1 cm) 7 to 15 days after hatching; Taisho Sanshoku will show ink-black during the rearing process, and although some are light ink, if those with better red patterns are selected, it is still advisable to keep them. Kohaku or Taisho Sanshoku, etc., can undergo the first selection about 40 to 60 days after hatching; some appear light ink in autumn but turn brilliant ink at the beginning of spring; others do not turn jet black until 2 to 3 years of age, or their crimson becomes more vivid. The selection work must grasp the genetic characteristics of various koi, and the criterion for selection is positioned by what quality of carp is to be produced. In the first selection, all those carrying the genetic characteristics of their variety should be retained. After that, about 20 days later, a second selection should be carried out, and they should be stocked separately in ponds according to different varieties and specifications to improve the survival rate of the koi.