The giant cod is making a comeback after being overfished in the wild and the financial backers of this venture are confident they can receive a 25 per cent premium for live fish.

After several years of research and development, 800-gram cod that have spent the past year in grow-out tanks are being moved into clean water and anaesthetised for their road journey to distributors and restaurants.

Marianvale Blue, a $5 million joint venture on a picturesque farm near the Hume Highway east of Goulburn, has become the largest Murray cod producer in Australia.

From here the farm's investors hope to increase production to 200 tonnes a year and expand to Melbourne, Canberra and into south-east Asia.

The farm's first customer, live-fish supplier and wholesaler Thang Nguyen, is taking 300 kilograms of cod a week to Sydney.

Private company Sustainability Ventures, which started six years ago to help diversity on family-run dairy farms in Victoria by re-using effluent, aquaculture and other money-making ventures, is behind the project.

Director Ayal Marek said the bigger scale Goulburn operation, with energy- and water-efficient innovation, was developed after a supply chain partner for the small Victorian enterprises fell through.

''Murray cod is unique to Australia. It cannot be fished commercially in the river, and several studies by Austrade and the Department of Primary Industries have shown great prospects in south-east Asia for exporting these fish,'' Mr Marek said.

Marketing spokesman Roger Camm said the strong dining-out culture of the Chinese and their liking for something different was an export opportunity for highly rated Australian fish.

''The middle-class Chinese spending power has increased and they are now able to purchase quality seafood,'' Mr Camm said.

''What is happening worldwide is the seafood catch in the wild is static, but the catch's efficiency is rising.''

Asia's aquaculture, although vast, was running out of options to expand because of over-use of chemicals and polluted waterways.

''The thing about fish is that they have to be in very good condition to grow well,'' Mr Camm said.

Murray cod are predators. Farm manager John Breen weans fingerlings from a diet of bugs to pellets, but his work is not finished.

They have to be graded every eight weeks, otherwise the big ones will eat the little ones.

''They are that aggressive. It's pretty important to keep the fish as uniform as possible,'' he said.