World's Most Expensive Fish
The world's most expensive fish sold for nearly a quarter of a million dollars in Tokyo January 5, 2012. (REUTERS)

The world's most expensive fish has been bought by a Japanese sushi chain in an effort to outbid foreign rivals.

Sushi franchise Kiyomura K.K paid a record 56 million yen ($730,000) at Tokyo's Tsukiji market for the 269kg bluefin tuna.

The previous record was set last year at just over 32 million yen.

The fish was carved into around 10,000 pieces of sushi that will be sold at the restaurant's normal prices of $5 apiece.

The resulting loss for the company is estimated to be more than $600,000 dollars.

"It is not just about the money," said Hiroshi Umehara a spokesman for the chain. "It is also about the Japanese spirit."

Foreign companies have outbid Kiyomura at the auction in the past three years, said Umehara, making it an issue of national pride.

"We really wanted to provide good tuna to the locals after losing to overseas rivals in the past three years," he added

"The purchase shows that Japanese companies still have stamina," said Masao Morita, Sony Pictures Entertainment Japan representative director.

Japan eats more fish per capita than any other developed country, and consumes about 80 per cent of all Atlantic and Pacific bluefins caught.

However, restrictions on catches have been tightened in recent years because of concerns about overfishing.

Atlantic bluefin tuna are one of the world's largest fish species, and are capable of reaching well over 450 kilograms in weight. The largest bluefin ever caught is thought to have weighed 679kg.