When fishmonger John Fragopoulus pulls on his apron and gumboots on Wednesday morning, he'll be looking forward to his 30th Christmas Eve trading day with the FishCo Fish Market.

"The retail demand for seafood here in Canberra is strong but everyone leaves it to the last minute of course," he said.

"We were open for 24 hours last year and it was ok – we made money sure – but it took me two weeks to recover so we're not going to do that again."

Mr Fragopoulus, who owns the Belconnen and Fyshwick stores, said his staff expected to sell more than 12 tonnes of prawns before Christmas Day.

"The Australian prawn farmers have done their homework this year and the variety is fantastic for the first time since I've been in this industry," he said.

Mr Fragopoulus said prawns would range from around $24 a kilo to $50 a kilo for wild catch tiger and king prawns, which would be his choice on the Christmas table.

"Farmed prawns can be very good but they just cannot compare with wild prawns," he said. "We've already had people pre-order 300 kilograms of wild prawns."

While prawns may be a plenty, Mr Fragopoulus said seafood fans should keep a trained eye for crayfish with limited supply coming from fishing crews.

"They haven't been catching enough crayfish to meet our demand and of course you have China and their countries interested so they are exporting fish and prices have escalated," he said.

Mr Fragopoulus said he hoped Christmas Eve trading would be a success for all fishmongers across the ACT as a quiet month was expected in January.

"Things tend to drop off after New Year's Eve because although we do get a good crowd of tourists coming through a lot of the restaurants are closed over the break so that drops sales," he said.

"January is traditionally the quietest time of year as a lot of fishermen take a few weeks off with their families to mend their nets, which is why the fish becomes so expensive."

But Mr Fragopoulus said there was no such luck for oyster farmers on the south coast who have face difficult conditions.

"A lot of rivers on the south coast have been closed so it's unfair for the oyster farmers who have been expecting a good run to pay their bills, but we still have oysters from other areas," he said.

Chris Russell, owner of Ocean Fresh Seafoods at the Fyshwick Market, said his store's "golden moment" was a fine selection of east coast lobsters at a competitive price.

"Catches on the east coast have been very light as our traps are on the continental shelf and they've haven't been on the march, but we've done very well and kept it under $100 a kilo," he said.

"We've also shipped in close to six tonnes of fresh tiger prawns from Queensland to cope with the demand," he said.