It's one of our rarest fish - and these schoolchildren have played a key role in restoring the dollaghan trout so that it will thrive in Northern Ireland's rivers once again.
The P7 pupils at St Mary's Primary School in Dunnamore hand-reared a small shoal of young trout from eggs in their classroom and have now released them into the Ballinderry River.
Not only will their efforts help to bring back the rare dollaghan trout - which is only found in Northern Ireland - but they are also helping to restore another rare species.
The river is home to a unique population of freshwater pearl mussels which is in danger of becoming extinct after dwindling to fewer than 1,000 individuals, and the trout fry form a key part of their life cycle.
Microscopic mussel larvae called glochidia live the earliest part of their lives within the gills of the young fish, where they cause no harm. When they are big enough they drop to the river bed where they live the rest of their lives - so bringing the trout back brings the mussels back too. As part of an educational project funded by the Heritage Lottery Fund, the children were given a batch of trout eggs early this year by Frank Mitchell who runs the hatchery at the Ballinderry River Trust which runs the project.
They were kept in a fridge in the classroom until the fry hatched. Once they were big enough to survive, Frank returned to the school to help the children release the young fish into the river.
The hatchery has been battling to improve the water quality in the river which had suffered from high silt levels, damaging the mussel populations.