The Natural Resources Institute believes the potentially harmful fish were brought into the country illegally.
Bitterlings originate from the northern Black Sea.
Image: Lauri Urho / LUKE
Natural Resources Institute Finland (Luke) said on Thursday that two new non-native species of fish have been found in a pond in southwest Finland.
The Natural Resources Institute suspects that the fish were illegally brought into the country and released into the wild.
The species, which have never been reported in Finland before, are the common nase (
Chondrostoma nasus) and the European bitterling (
Rhodeus amarus). The fish were found during a population study of another alien species, the pumpkinseed (