Juvenile brown trout have been found in a stretch of the River Medlock in a "massive step forward" for the recently restored wildlife habitat.
The Medlock, previously known as the Red River, underwent a £250,000 transformation at Clayton Vale, Manchester, in 2013 which re-naturalised the waterway to encourage habitats for wildlife.
The project along a 300-metre section of the river, just upstream of Philips Park and the Etihad Stadium, included the removal of the brick lining, the digging up of concrete foundations and the widening of the watercourse.
Two weirs were removed which slowed the flow of the water and deep pools were created to help with water quality by reducing sediments.
The brown trout, a key indicator species, were found in the river following a fish survey in April.
The Medlock was originally modified more than 100 years ago by lining the channel with concrete and bricks to provide essential power and resource for local industry, but damaging natural habitats in the process.
It became known as the Red River after eight million bricks were used to channel the water following the Great Flood of 1872 when the Medlock burst its banks and washed away tombstones and bodies from Philips Park Cemetery.
Oliver Southgate, the restoration project manager from the Environment Agency, said: "Finding juvenile brown trout in the Medlock is a massive step forward as it shows we have created suitable spawning habitat in the river.
"These fish are a key indicator species, which means the overall ecology of the river - good water quality and habitats for fish - have markedly improved.
"Our mission at the Environment Agency is to make this a better place for people and wildlife and I'm really proud of our work to bring this river back to life. Further work on the Medlock is planned and I really hope the local community come and enjoy this city oasis."
Manchester City Council's executive member for the environment and skills Angeliki Stogia said: "It's wonderful to know that our partnership work is paying off and that nature is responding so impressively to the restored habitat along the River Medlock.
"This project has benefited both wildlife and local residents by enhancing a fantastic place for nature-lovers, walkers, families and anglers, within just a couple of miles of Manchester city centre."