Koi

The temperatures are hotting up over in Niigata, where Mark Gardner is getting stuck into the Koi breeding season...

As June draws to a close, summer is truly upon us in Niigata. Daytime temperatures are already stretching into the low 30˚Cs. During July it’s likely that the temperatures will be over 35˚C. As attractive as those temperatures may sound, it can become too hot for the Koi in the mud ponds.  The temperature of the water can put them off feeding and also the lack of fresh water from rain can cause the pond water to deteriorate.
This is also the start of the busiest time for the Nishikigoi breeders. Having spent the last six weeks undertaking breeding, in the process producing millions of tiny fry, they now have to cull in order for the Koi with the best potential to be given the maximum opportunity to fulfil it.

Culling of most varieties starts at around 40 days old – the black-based varieties such as Showa and Shiro Utsuri are culled at just one week old when only dark coloured fry, or Kuroko, are kept. 

At this age the fry bear little resemblance, and offer only a hint of the potential, of what they may become. With Kohaku, for example, the breeder is looking for the presence of just orange and white colouration, making some form of discernible pattern. Those with undesirable traits such as being menkaburi (meaning hooded – the Koi has a completely red head) or bozu (meaning bald) are discarded. In addition, anything with visible deformities is also discarded.

Each day will be filled from dawn to dusk carrying out the first cull, a process which for most breeders will take up the next four weeks, before the process starts again with the second cull. By the time the young Koi are harvested in September this process will have been repeated maybe as many as four times.

It’s a time-consuming process  but an essential one for producing high-quality Nishikigoi.