Oyama Koi Farm: Ginrin That Lasts, and Chagoi with Metallic Fins

The road up to Oyama Koi Farm is narrow, steep and, in winter, slick. Zak's take as we climbed it: "This is the test. If you can survive and not fall off, you're allowed to buy koi from him." We survived, and this turned into the visit from the 2026 trip that people have watched the most.

Oyama is in the hills outside Hiroshima, a long way from Niigata, and the setting is as pretty as any farm we go to. Mr. Oyama is also, in Zak's words, "a really smart breeder, very articulate." He explained more about his own fish in an afternoon than most breeders do in a year, which is why the visit ran long and the buying ran over budget.

Why most Ginrin disappoints, and his doesn't

Ginrin is the sparkling scale. It looks irresistible on a small koi, and that is the problem. "When you buy Ginrin koi with the silver scales when they're small, almost from any koi farm, you look at them and they look so shiny and you're like, oh, they're going to be great."

What makes a scale sparkle is tiny wrinkles in it. As the koi grows, the scale grows with it, and the wrinkles stretch out. A fish with only a few wrinkles per scale goes from shiny at two inches to flat at two feet. A fish with many wrinkles keeps its shine as it grows. The catch is that at tosai size you can't see the difference; every small Ginrin looks shiny. You can start to see it once the fish is around hand-sized, when the better ones still show the fine texture across each scale.

This is Oyama's specialty. Mr. Oyama said it himself and Zak saw it in the fish: even the larger koi in his ponds were still intensely shiny, because the wrinkles are so dense. "The Ginrin is so strong because there are so many wrinkles in the scales." That is what you are paying for when you buy a Ginrin koi from a farm known for it rather than from anywhere.

Chagoi with metallic fins

The fish that stopped Zak were the Chagoi. A Chagoi is the plain brown koi, the friendly one that eats from your hand, and its pectoral fins are normally orange-brown or fade to clear. Oyama has been breeding Chagoi whose body is a normal Chagoi but whose pectoral fins are metallic, opaque and shining like a Hikarimono. "The body is normal for the most part, and then the pectoral fins are just shiny." Zak had never seen it before, and bought around sixty Chagoi tosai from that group. "It makes them stand out."

White Asagi, on purpose

One of his ponds was full of young Asagi with almost no red on them, and people ask him why. His answer is the same logic that runs through the whole trip. The Asagi that end up at shows, the best ones, start their red late. The beni comes in as the fish gets older, and a young Asagi that already has a lot of red is not the one to buy. On some of his you could see just a touch of beni starting on the pectoral fins. "As it gets older and older, then the red should come in. But that's something you have to be patient for. You can't just expect it to look amazing when it's young."

He said something similar about his Mukashi Ogon, the old-style metallic. The darker young ones, the ones that look "kind of ugly and black right now," are the ones with the chance to grow biggest, and their beauty shows later. It is the same rule we learned about choosing Kujaku dark at Omosako: you are buying the future koi, not the one in the bowl.

What we bought, and how

His tategoi pond, the fish he keeps for shows, growing on and parents, was not for sale, and by the time we arrived he had sold almost everything else; a couple of the big ones were being held for customers. Mr. Oyama helped Zak pick two metallic koi from what was left, variations of silver and gold Ogon, both with that dense Ginrin and good skin, and those came back to Miami.

Then there were the tosai. He offered to let Zak choose a mix himself. Zak's answer: "Honestly, who's going to choose better, me or him? So I asked him to choose, and he's going to send me a box of 50 of this mix." Plus the sixty Chagoi. "I just had to buy more than I originally planned because I know they're so good."

That is worth saying plainly because it is how a lot of our tosai are bought. Older koi we choose one at a time, and each is listed with video of that exact fish, its size, sex and year born. Tosai come both ways: some we pick out of the pond ourselves, and some, like Oyama's box, the breeder chose for us, in which case the listing covers a group of young koi rather than one named fish.

Buying a Ginrin koi from us

Use the wrinkle test. On a small Ginrin from any farm, the shine tells you almost nothing. On a koi that is already a foot long, look across each scale: if you can see fine texture rather than one flat reflection, that sparkle will survive growth. The farm's reputation for Ginrin is the other half of the answer, which is why Oyama's name on a listing matters to us.

You can see the whole visit above. The rest of the trip, including the other Hiroshima farms, is in how buying koi in Japan actually works, and if you are starting with young fish, read our guide to buying tosai.

Browse our Oyama koi, all Ginrin koi for sale, or every koi we currently have available. Live koi ship Tuesdays and Wednesdays, anywhere in the USA.