A tour of Tokyo's largest fish market

Something's fishy at a busy Tokyo market, much to the delight of restaurant patrons all over town. Seth Doane now, with a very pricey fish story:

It's the fish, the knife, and a little rice. There's not much else.

At his Tokyo restaurant Isana, chef Junichi Onuki said that in this fish-obsessed city some customers expect the seafood to come from a certain market. That market, called Tsukiji, is Tokyo's largest. It's packed with every type of seafood imaginable, from brightly-colored octopus and shrimp, to king crab and tiny sardines.

Chef Onuki is usually here by 8 a.m., searching for inspiration, changing his menu as he shops: "I found this squid. Okay, let's make some tempura tonight."

More than $4 billion worth of seafood passed through Tsukiji in 2013. This island nation of Japan has less than two percent of the world's population, but consumes 10 percent of the world's fish.

Thirty-thousand tourists a year come to see the giant tuna lined up for auction.

Alana Toolie is from Chicago: 'We have Lake Michigan, we have fresh fish, seafood, but nothing like, where it looks like the fish just got out of the water and then you just sell it. So this is just amazing!"

Toolie is a teacher, and a foodie, as her iPhone photo gallery can attest. "I had salmon and super fatty tuna which I love! Like I would marry it and eat it every day!"

Frozen from far-off waters, the giant tuna are poked and prodded to determine value. The fattier tuna and the tuna with a bigger belly will generally fetch a better price.

Fish at Tsukiji comes from all over the world, as far away as Australia or South Africa.

Tuna regularly sells for tens of thousands of dollars for a single fish. Last year, one bluefin set a record: selling for $1.7 million.

Toi Chio Ida -- an eighth-generation fish monger who sells to chef Onuki -- paid $40,000 for a single tuna on the day we were there.

That, said Doane, is roughly $2,000 per piece of fish."That's hard to believe."

"But we don't get much profit," said Ida. "Our average profit is around 20 percent."

Bluefin can be up to 10 times more expensive than other types of fish, something restaurants sell just to draw in customers.

Little has changed at Tsukiji in its nearly 80 years. But within two years this market will likely be torn down and relocated as part of a "modernization" plan ahead of the 2020 Olympics.

Junichi Onuki says, "We can't do this job without Tsukiji fish market."

Onuki says sushi's simplicity is what makes it so difficult to master. But, at the very center of it all, is getting the best fish.

For more info:

• Isana Sushi Bar, Tokyo
• Tsukiji Fish Market, Tokyo