A radical project to relocate 70,000 fish eggs in an effort to save a rare breed has proved successful.
Lake Bassenthwaite is home to rare species of fish
The eggs, from endangered vendace, were taken from Bassenthwaite Lake, Cumbria, to Loch Skene, in Dumfriesshire.
The move followed fears that poor water quality and pollution in Bassenthwaite could wipe out the whitefish, which can be traced back to the Ice Age.
The fish are now doing well in their new Scottish home and a second Lake District lift is planned this winter.
Historically, vendace were recorded at four UK locations - Bassenthwaite, Derwentwater, Castle Loch and Mill Loch in Dumfries and Galloway.
The Castle Loch population disappeared at the beginning of the 20th Century and Mill Loch shortly before the end.
The Environment Agency's senior technical specialist Cameron Durie said: "Adult fish caught in Bassenthwaite in 1997 and 1999 provided eggs that were hatched and the young fish introduced to Loch Skene.
"Evidence shows a vendace population has become established."
Past attempts to transfer eggs from Derwentwater have failed.
This winter, 100,000 eggs will be transferred to Daer Reservoir in southern Scotland.
It is hoped that some will also be used to establish a vendace population in an upland Lake District tarn.
The fish is protected under the Wildlife and Countryside Act (1981).
Mr Durie said vendace populations in Bassenthwaite and Derwentwater were "very fragile" and the threats facing them were considerable.
He said: "Vendace have a range of serious problems to contend with, from sewage and fertiliser washed off fields by the rain, silting caused by erosion and earth washed in from surrounding land, to competition from other species."
A Bassenthwaite Lake Restoration Programme is currently under way with a 20-year mission to make the waters as clear and clean as they were 60 years ago.