Koi Breeder Mud Pond Harvests
- Kevin Warren
- Nov 23, 2025
- 2 min read
Updated: Dec 23, 2025
Koi Mud Pond Harvests in Japan
Every autumn in Japan’s koi-breeding regions, the quiet mud ponds begin to come alive. Koi breeders, farmers in their own right, walk the mud-pond banks before sunrise, checking on their prized Nishikigoi and the condition of the ponds themselves. Water levels naturally drop by the end of September as temperatures fall with the changing season.
Preparing for the Mud Pond Harvest
It’s time to prepare for the harvest, and many tasks must be completed. Ponds need to be lowered to a level that allows the use of seine nets to gather the koi. The nets themselves are checked and repaired if needed. Water channels must be cleared so the water can make its way down the mountain from the mud ponds. Indoor ponds—where the koi will be moved—are also inspected to ensure they are ready.
How Many Ponds Does a Koi Breeder Manage?
As I list the work that has to be done, consider that each koi breeder doesn’t have just one mud pond. A very small breeder may have a few ponds; a breeder like Marushin will have around 80 ponds; and the larger breeders may have 100 or more. Mud ponds also range in size, from shallow, one-eighth-acre ponds for raising newborn fry to large, lake-like ponds that are meters deep for raising jumbo koi.
The Mud Pond Harvest Process Begins
The Koi breeder mud pond harvests begin with near-precision timing. Breeders and their employees descend on their mud ponds like bees to a hive. Their day begins as the sun rises, gathering first at the farm to load the small K-trucks with equipment and holding tanks for the koi, then it’s off to the ponds.
Accessing a Mud-Pond Harvest
While not all koi breeders welcome the public or cameras during their harvests, some are happy to share the experience and work with trusted clients. If you are interested in watching or participating in a mud-pond harvest, and you are a buyer in good standing with a dealer who visits Japan during the harvest season and can provide access, you too can take in this remarkable cultural experience. Start with this article, here in Koi Waters, about koi breeder visits with accredited agents.
For Those Who Cannot Attend
For those who can’t make the journey to the heart of traditional Japanese koi culture, Ikeage, I hope these photos offer insight.
As always, a special thank you to the following Breeders who have been so generous in working with me on this and all the stories here on Koi Waters Online Magazine.
Mitsuhiro Tanaka talks to his employee before a mud pond harvest Marushin Koi Farm preps for a mud pond harvest Marushin Koi Farm preps a small pool to hold koi during a mud pond harvest One of Yagenji Koi Farms mud ponds in the Niigata Prefecture mountains Yegenji Koi Farm preps for a mud pond harvest by placing pools to hold koi Toshinori Ishihara of Yagenji Koi Farm inspecting his koi mud pond Mitsuhiro Tanaka, Marushin Koi Farm, using seine nets to gather koi from a mud pond The Marushin Koi Farm team harvesting koi from a mud pond Team Marushin Koi Farm pulling in seine nets full of koi from a mud pond Marushin Koi Farm places koi from the pond into a small pool so they can bag them to be transported Yagenji Koi Farm employee pulling seine nets at a mud pond Lucky buyers attend and help at a Yagenji Koi Farm mud pond harvest. Toshinori Ishihara, pulling in his seine nets Marushin Koi Farm harvesting jumbo koi from one of their secret ponds Daisuke Ishihara carrying bagged koi from the mud pond to a K-truck holding tank Jumbo Koi from a Marushin Koi Farm mud pond Mitsuhiro Tanaka putting a jumbo koi into his trucks holding tank Marushin Koi Farm moving koi from the mud ponds to their indoor ponds at the farm Inside one of Marushin Koi Farms indoor pond houses Mr. Scarecrow worked all summer protecting a now empty Yagenji koi mud pond
