Competition organiser Brylee Percy, of Glenorchy, said the catch was possibly one of the biggest in the competition's 40-year history.
"It's one of the biggest fish I've ever seen pulled out of the lake," she said.
She said the weather was "lovely". A Fish and Game New Zealand ranger deemed the condition of fish the best he had seen in at least eight years.
Shelby Joyce (4), of Palmerston, won the junior/child category with an hefty 1.348kg brown trout.
A total of 127 people, aged from 2 to 80 years, entered the Glenorchy Netball Club-organised fundraiser.
About $2000 was raised for the club towards lights on the netball court, which would be installed before the next winter, she said.