Hundreds of young fish were set free into the waterways of Bolton after being reared from eggs by school children.
The Environment agency gave hundreds of brown trout eggs to pupils across the borough in January.
And after watching them grow over the last 12 weeks, the youngsters released the fish in Eagley Brook to begin their lives in the wild.
Children from St Andrew and St Osmund RC Primary School in Breightmet, St Ethelberts RC Primary School in Deane and St Andrews CE Primary School in Over Hulton took part in the project.
The scheme aims to boost the number of the fish in a six-mile stretch of Eagley Brook after the entire brown trout population was destroyed following a pollution spill.
Headteacher at St Ethelbert's, Mandy Messham, said: "The children got to understand all about life-cycles and learned about caring and nurturing. We're also doing something to help the environment and have produced posters and poems.
"It's been a fantastic experience for the children and has got the whole school talking."
Nicola Hails, Year Five and Six teacher at St Osmund and St Andrew's, added: "The children have been able to watch the fish grow, which has been great for them. We've also produced artwork, as well as learning about science and maths."
In September 2006, an estimated 10,000 fish died after two poisoning incidents in less than 24 hours on a six-mile stretch of Eagley Brook.
The fish were believed to have been poisoned by fly-tippers who tipped acid into the brook as many of them had burn marks.
Last year, the Environment Agency released more than 6,000 fish into the river but wanted to involve local children and handed over tanks, coolers and the fish eggs to the three primary schools.
Ian Hayes, the Environment Agency fisheries officer, said: "This has been a great, hands-on project giving pupils the opportunity to learn about life-cycles, food chains and habitat as they watch eggs hatch, rear them and then finally release them."
Story from The Bolton News