The koi in our late October drop is not in San Jose. It is in a tank at a farm in Niigata, photographed and filmed the same week it came out of a mud pond, and you can buy it right now. Japanese breeders empty their mud ponds every autumn. We fly out and buy while they do it, and the fish go up on this website from Japan. That is what harvest season means here. This is how it works, from the mud ponds of Niigata to your backyard.
Short answer: Japanese breeders net their mountain mud ponds from October into December. We buy direct from the farms through October and November, photographing and filming every koi as we go, so it goes up for sale here within days, while the fish is still in Japan. Autumn is the widest selection you will see all year. The Quarantine Completion Date on each harvest listing tells you when your koi will be ready to ship, so you set the delivery around your pond.
What a harvest actually is
In spring, a breeder moves his best young fish into a mud pond in the mountains and leaves them there all summer. The mud pond gives them what no concrete tank can: natural food, room, and water the breeder does not have to make. In autumn the ponds must be emptied before snow closes the mountains, and emptying one is a full-crew job that runs on bare hands and plastic bags.
The breeder drains the pond first, down to the last little water, so the koi are concentrated in one small area. The staff walk a large net around the perimeter of the nearly empty pond, then draw it in from one direction, herding every fish together. Then the catching starts. One at a time, by hand, each koi is lifted out of the water and into a small floating pool or a big blue bowl holding a few inches of water.
Getting the fish up to the trucks is a human chain. The crew forms a line from the koi at the bottom of the pond up to the truck beds at the top, where oxygenated tanks are waiting. Each koi is bagged out of the pool, one bag for a large fish, a few smaller ones to a bag, and the bags pass hand to hand up the line until the last person on the truck bed releases the fish into the tank. One mud pond can fill four or five trucks.
The trucks drive down to the breeder's greenhouses, the line forms again, and the koi are passed, bag by bag, into the greenhouse tanks. Those tanks are where we buy them.
That is the harvest. The timing is set by weather, not by anyone's sales calendar. Breeders run it from October into December. We buy through October and November.
What a buying trip actually looks like
We fly into Niigata. By the time we land, our agent in Japan has already done the hardest part of the trip. She knows which breeders are harvesting and when, which farms have sale days, what kind of sale each one is, and which farms have anything new worth the drive. That schedule cannot be built from California. It moves with the weather and with what comes out of each pond, and she works the phones for weeks before anyone boards a plane.
Then it is farms, all day. Five in a day is normal. Ten is possible. When there is ground to cover we split up, so Noy, Eli and I take different farms, and some years Justin or Paul comes along and buys us another set of eyes.
The three kinds of sale you walk into
Farms do not all sell the same way, and the format decides what your preparation is worth.
An open sale is what it sounds like. Anyone can buy, in no particular order, so the advantage goes to whoever arrives first. Standing at the farm when the koi come off the truck, or being at the gate when it opens, is most of the game.
A lottery is not a draw for a fish. It is a draw for picking order. Every dealer takes a number. The lowest number chooses first from the group on offer, then the next, and on your turn you either take a koi or pass. After the highest number picks, the order reverses and runs back up to number one, so the last dealer picks twice in a row. Anyone who has run a fantasy draft will recognise the shape of it.
Drawing a high number costs real money. By the time your turn comes, the fish you drove out for may already be in another dealer's bowl, and no amount of experience changes that.
At an auction, the koi is bowled and walked up the floor and back so the whole room gets a quick look. Then the bidding starts. Every bid in that room rests on the same few seconds of looking. Worth remembering the next time you replay the video on one of our individually photographed koi for the fourth time.
“When the timing works, the breeder lets me inspect the koi as they come off the truck, straight from the transport tank into the viewing bowl. That is the most thorough look you will ever get at a fish. I go through each one for deformities, body conformation, skin quality, colour development and pattern, and anything that does not meet my standard goes back. The hard part is that you rarely get to take your time. Other buyers are waiting, the day is short, and there is only so much room in a shipment. I have passed on a few koi over the years that I still think about.”
Tom Lai · Owner, ChampKoi
What the day costs
Five to ten farms is the buying. Then the day keeps going. Customer requests get answered from the hotel. The koi bought that afternoon get photographed, filmed, written up and posted. The next day's route gets replanned around whatever our agent heard since morning. By the last week of a trip, nobody is pretending it is a holiday.
Why our koi go up for sale before they leave Japan
We list our harvest koi from Japan, while we are still buying.
The cycle is simple. Buy until there is enough for a shipment. Ship it. Keep buying for the next one. Last year that was four shipments. Because every koi is photographed and filmed at the farm, the listings get built on the road and go up in drops every three to five buying days. A koi you buy from us in late October may still be swimming in Niigata when you pay for it.
That is a deliberate choice, and it is what the evenings go on. It gives you the run of the selection while the harvest is still happening, instead of whatever is left at the end of it.
What the Quarantine Completion Date means
Every harvest listing carries a Quarantine Completion Date. It is the most useful line on the page.
The sequence runs like this. We buy the koi in Japan. When there is enough for a shipment, our agent sets a ship date. From that we work out when the fish will have landed, completed quarantine at our San Jose facility and passed its health checks. That date goes on the listing as the Quarantine Completion Date, or QCD, and you choose a delivery date on or after it.
If a listing has no QCD yet, you can still check out. That reserves the koi, and we contact you for a date once it is ready to ship. Our order process guide covers the rest of the mechanics.
Two things follow, and both are worth saying plainly. Your fish does not ship the day after you order, which is the point: nothing leaves this facility before it has finished quarantine and been screened for KHV and spring viremia of carp at a USDA-certified fish health laboratory. And reserving is how you get a harvest koi at all. Every fish we sell is a single fish with nothing behind it. When it sells, it is gone.
Do harvest koi change after they settle?
A little, and mostly the young ones. A two-year-old nisai that came out of a mud pond in October is not a finished fish, and some of what you see in the bowl will move over the following weeks.
If a koi changes enough that what you bought looks meaningfully different from what was photographed, we contact you before it ships and you decide. Nothing goes in a box that you have not agreed to.
Receiving a fall harvest koi
Many of our customers buy from the fall harvest every year and settle their new fish without a problem. The routine is not complicated. It just works better when it is ready before the box arrives.
Give the fish two to three weeks in an isolation tank before it joins your pond. You are not repeating our quarantine. Every koi we import is laboratory-screened before it ships, so the tank does not need heat. Run the praziquantel course anyway, because flukes are close to universal on shipped koi and no virus screen touches a parasite. Our quarantine guide has the protocol, along with the full heated version for fish from anywhere you cannot vouch for.
Put the tank somewhere temperature-stable: a garage, a basement, a spot that does not track the overnight air. Keep an ammonia and nitrite test kit on it, and step the tank toward pond temperature before release.
The one seasonal number to know is your pond's feeding band. At 55 to 60°F koi feed once a day, and below 50°F they stop for the winter, so a new fish wants enough time in the pond to settle and eat before the water gets there. Our feeding guide has the full temperature chart, and the winter care guide covers the pond itself. If your season is further along than your setup, that is what the delivery date is for: reserve the fish now and talk to us about timing. Setting the arrival around your pond is a normal conversation here.
Why the breeder's name is the part you can check
Very little in this trade can be verified from a photograph. The breeder's name is one of the few things that can.
Every koi we sell comes from a named farm with a history you can read. Take Ogata, which is in Kurume, in Fukuoka rather than Niigata, a separate flight and a separate day on the trip. The farm has been breeding since 1972 under Manabu Ogata, who trained under Ichiro Mano at Izumiya in Niigata. A homebred Ogata Kohaku took Grand Champion at the All Japan Nishikigoi Show in 1987. You can read that, and the same for the rest of them, on our breeder profiles. A grade is a word a seller chose. A breeder is a fact.
If you want a koi from this harvest
Set up the isolation tank before you buy rather than after. Watch the drops, because they land every few days through the trip and the good fish go early. Reserve rather than waiting for the fish to arrive, since there is only one of each. Check the QCD and pick a delivery date you can be home for. If you are not sure what variety you are looking at, keep the varieties guide and the koi encyclopedia open while you browse.
Where to start
If your pond is running and you have an isolation tank, this is the best buying window of the year. Reserve early in a drop, and read the Live Arrival and 7-Day Health Guarantee before the box lands rather than after, particularly the two-hour window for a DOA claim.
If the isolation tank does not exist yet, reserve the fish anyway and take a later delivery date. The tank is a weekend job and the cheapest equipment you will buy in this hobby, and the QCD system exists precisely so the fish can wait for you instead of the other way around.
Frequently asked questions
When is the Japanese koi harvest?
Japanese breeders harvest their mud ponds from October into December, with the timing set by mountain weather rather than a fixed calendar. The ponds have to be emptied before snow closes the mountains. Most dealer buying, including ours, happens through October and November, which is when the widest selection reaches the market.
Can I buy koi directly from Japan?
Not as a hobbyist, in practice. Breeders sell to dealers and exporters, and the import chain involves USDA APHIS inspection and health certification built around commercial shipments. What you can do is buy from a dealer who selects at the farms in person, which is what our harvest listings are.
What does tategoi mean?
Tategoi is a koi the breeder judges still has development ahead of it and holds back to grow on rather than selling. Tateshita is a fish that was not selected to be kept. Both terms describe a breeder's judgement about a specific fish at a specific moment, so the word is only as good as the person using it.
Why are koi grown in mud ponds instead of tanks?
Mud ponds give a growing koi natural food, room to move and mineral-rich water that a breeder cannot replicate indoors. Fish put on size and body in a way that concrete does not match. The trade-off is that the breeder cannot see them properly for months, which is exactly why the autumn harvest is such an event.
Is autumn a good time to buy koi?
It is the best time of the year. The selection peaks because the year's fish have just come out of the mud ponds, and many of our customers buy from the fall harvest every year. Have your isolation tank ready, check the Quarantine Completion Date on the listing, and pick a delivery date that suits your pond.
How long does a koi stay in quarantine before it ships to me?
Until it has completed quarantine at our San Jose facility and passed its health checks, including laboratory screening for KHV and spring viremia of carp. Nothing ships before that. The expected date is published on each harvest listing as the Quarantine Completion Date, and you choose a delivery date on or after it.