The Environment Agency said its staff were amazed to find a dead piranha in the East Okement tributary of the River Torridge.
The piranha, which has razor-sharp teeth, is generally considered to be the most ferocious freshwater fish in the world.
The 35cm (14in) fish was spotted by Bob Collett, Dave Hoskin and Eddie Stevens during a sampling trip on the river.
Fish species which the team would commonly expect to find within the river include Salmon, Brown Trout and possibly other species such as Bullheads, Stone loach and Minnow.
‘What we actually discovered was something we would not expect to find in our wildest dreams. We could hardly believe our eyes,’ said Eddie Stevens, from the Environment Agency.
Source: Environment Agency