A fortnight went by with Basil Te Aho pottering around his Darwin kitchen, clueless to the fact there was $10,000 in his freezer.

But last night, he decided to cook the barramundi he caught with his 83-year-old father, Kimgi Te Aho, at Yellow Waters two weeks ago.

As he went to clean it, he noticed a small, red tag with the date — March 31, 2019.

"I wasn't quite sure, but I was more excited that it might have been a million-dollar fish," he said.

As part of the Million Dollar Fish tourism campaign, 100 tagged fish have been released into Top End waterways that will win the catcher $10,000, if caught before the end of March next year.

There are also five $1 million fish.

After a quick call to the campaign operators, Mr Te Aho realised he was a winner.

"There was fist raising everywhere," he said.

"I told [my dad], he was pretty excited."

He had no idea of the windfall when he caught it two weeks ago.

"We went to Yellow Waters and were just trawling along the lagoon," he said.

"And this thing hit my line, [I] pulled it in and there it was. Got it on the boat and put it in the esky straight away.

"[Then I] come home, stuck it straight into the freezer. Then went straight to bed, because I was that tired."

This is the second tagged barra caught this season — and both have been caught at Yellow Water billabong in Kakadu.

He said he would probably give some of the money to his dad, some more to his family and spend the rest travelling to his hometown of Wairoa in New Zealand.

"We actually live on the beach … I go about January, February, when the salmon come in. The relations are a bit lazy to go fishing," he said.

After the excitement of the last two days, Mr Te Aho said he was already planning his next trip.

"I'm going to have a go at Corroboree maybe tonight. And probably next month I'm going to head out to Yellow Waters again."

Although he never got the chance to eat his dinner last night, he said he would probably smoke the lucky fish today.