But it was just a humble brown trout - all 4.426kg and 832mm of it.
Mr Templeton, a first-time entrant in the annual fishing competition, was flabbergasted and delighted with the fish he hooked from a boat in a deep part of the lake near the Hunter Woolshed.
"I knew it was a huge one because it was 102m down," he exclaimed.
Mr Templeton, who owns Cromwell Mitre 10, usually enters the Cromwell fishing competition on Lake Dunstan but decided this year to fish with friends in the two-day Lake Hawea competition as well.
"I've never caught one this big before," Mr Templeton said.
"It took us 20 minutes to haul in, putting up a fight.
"One of the boys said, `What sort of fish is this.
"Is it a shark?'."
Mr Templeton was considering getting the fish mounted.
That may cost about $1000 but the $500 prize would be a good start towards it, he said.
One angler was treated by St John for heatstroke on Saturday.
Kerry Hondelink caught a 7.701kg (17lb) brown trout the day after the fishing competition in 1997.
It was mounted and hangs above the Lake Hawea Hotel bar.
Russell Dyet caught a 6.795kg (15lb) brown trout in the 1999 competition and it too hangs above the bar.
Jimmy Cotter caught a 7kg (15.5lb) brown trout during the 2004 competition and got it mounted. Category winners results. -AdultsHeaviest fish overall: Toby Templeton, brown trout 4.426kg.
Friday fishing: rainbow, Michael Fitzgerald, 2.938kg; brown, Ross Begg, 1.988kg; salmon, Richard Mair, 1.396kgSaturday fishing: rainbow - John Fitzgerald, 2.726kg; brown - Toby Templeton, 4.426kg; salmon - Maurice Cleland, 1.424kg.
Children/junior/young adultHeaviest fish: Cholena Perry, rainbow, 2.028kg,Junior/young adult fishing: rainbow - Cholena Perry 2.028kg; brown - Conor Rutherford, 1.678kg; salmon - Jordan Bolger, 1.368kg.
Children under-12: rainbow - Michael Hutton, 1.814kg; brown - Princess Adcock, 1.262kg; salmon - Hamish Shea, 1.32kg.
