Volunteers with the Walleyes for Tomorrow were watching one cylinder full of nearly 5,000 fish eggs, waiting for them all to hatch.
"They're going now," said Volunteer, David Borski.
Many of the fish already hatched and volunteers waited for the rest.
"About 200 will survive, to make it to the 15 inches to go out and spawn again," said Borski.
The Central Wisconsin Chapter of Walleyes for Tomorrow released nearly 200,000 newly-hatched fish into the Big Eau Pleine Reservoir near Mosinee.
"We're going to siphon them out or we can dump them just on the top layer of the water," said Walleyes For Tomorrow Chair, Kim Borski.
Kim Borski said members developed the project to help boost the number of fish in the reservoir.
The came after hundreds of fish were found dead on the Big Eau Pleine's shores earlier this year.
Wildlife officials said low oxygen levels in the water caused the fish kill, along with another major fish kill on the reservoir in 2009.
"There's a lot of dead fish, but most of them were carp, really, we did find some walleyes," said David Borski.
But efforts to restock the water at the reservoir take time and patience.
"You rub their belly and the eggs will just naturally come out, they just naturally release them if they're ready," said Kim Borski.
The group set up a hatchery, using water pumped from the reservoir, to get the hatched fish ready for release.
"So we take them back in, the water's going to be the same temperature," said David Borski.
Group leaders said this project will continue for at least three years and by that time, they hope to see results.
"It takes about three to four years for them to be about 15 inches," said Kim Borski.
Members hope their efforts can keep more fish alive at the Big Eau Pleine.
"You feel good, just giving back to the community and giving our kids something to look forward to, to have fish, for the future," said Kim Borski.