Close to 100,000 fish could be in the lake, which ran dry from 2006-10, thanks to the Department of Environments and Primary Industries and donations from a local hatchery.

Frank Gray, of the Ballarat Fish Acclimatisation Society, said Ballarat Fish Hatchery had put 6000 trout in the lake each year since 2010.

"It's fishing pretty well at the moment....a lot of people are coming from Melbourne to fish the lake," he said.

Four pipelines - Paul's, Redan, Ring Road and the Gong - transport water to the lake and Mr Gray said the water quality had created a thriving fish population.

Ballarat Anglers Club president Craig Hon said the lake had re-earned it's reputation as one of the best waterways among the fishing community of Victoria.

Mr Hon expected close to 10,000 people to fish the lake over the next six months.

A lot of "out-of-towners" were coming to fish the lake, according to Mr Hon, who said Williamstown Angling Club recently stayed at the lake.

Lake Wendouree was dredged by Victorian Marine Services in late 2011 for the benefit of rowers and local water sports, which Mr Hon said had improved the underwater environment for the trout hatchlings.

"The fishing has just started to thrive again ... it's a 100 per cent out of this world," he said.

Most anglers were pulling out 2kg fish, with some averaging close to 2.5kg.

Lake Wendouree has a capacity of 3300 megalitres and is almost "over full" for the World Rowing Masters Regatta Ballarat, held annually on October 9-12, Mr Gray said.

He said during the height of the drought the hatchery had to use diverted water from a City of Ballarat-owned bore.

"If we didn't have that we would have shut the gates," he said.

The 19th century hatchery, which is run by 20-30 volunteers, also received a $63,000 heritage grant from the state government in 2012 for restoration work, which Mr Gray said had been crucial for local fishing.