Fish
Topmouth Gudgeon
Pseudorasbora parva · also called stone moroko
In a small pond in Europe, a shoal of topmouth gudgeon cruises near the surface, tiny fish that arrived on the other side of the world from a carp farm.
Overview
The topmouth gudgeon, Pseudorasbora parva, is a Least Concern carp relative native to eastern Asia and a notorious invader across Europe. Its fast breeding, tolerance, and parasite make it one of the most damaging small invasive fish in European fresh water.
A tiny fish with a big impact
Because it spreads easily, breeds rapidly, and carries a parasite harmful to native fish, the topmouth gudgeon is the target of control and eradication efforts in many places.
Status
Least Concern in its native range, and invasive in Europe.
Topmouth Gudgeon: common questions
Why is the topmouth gudgeon a problem in Europe?
It breeds quickly, spreads easily, competes with native fish, and carries a parasite that can infect and kill native species.
How did the topmouth gudgeon reach Europe?
It was accidentally introduced in the 1960s, with shipments of Chinese carp, and then spread across the continent.
How big is a topmouth gudgeon?
It is a small fish, usually only 6 to 9 cm long.
Where is the topmouth gudgeon native?
It is native to rivers and lakes of China, Japan, Korea, and the Amur basin in eastern Asia.