An investigation is underway after a number of fish were reported dead at Buittle reservoir near Dalbeattie.
The mysterious deaths were reported by local anglers, and fishing experts are now trying to determine the cause.
The reservoir has been closed while the investigation takes place, but there is not currently thought to be any threat to people, or long term consequences to fishing in the area.
The deaths were reported to the Dalbeattie Angling Association.
They are working with the Fisheries Trust, the Scottish Environmental Protection Agency and Scottish Water to determine the cause.
The reservoir supplied water for Dalbeattie town until the 1960s, and has been used by the Dalbeattie Angling Association for more than 50 years.