Topmouth gudgeon

Pseudorasbora parva


Habitat: Well vegetated small channels, ponds and small lakes


Description: This is a small fish (up to 97mm) species that resembles the native gudgeon except in that its mouth is pointed upwards, allowing the species to feed on the surface of the water. 7 ½ branched dorsal rays, 6 ½ branched anal rays.


Origin and Distribution: Originates from South East Asia. The species has invaded lakes in England and Wales and the Environment Agency has implemented control measures.


Impacts: The species can severely impact on other fish species by eating their eggs. However, this species is known to have a breeding rate that is four-times faster than native fish and is a carrier of a parasite, similar to, or possibly the same as, a disease called the ‘rosette agent’. Topmouth Godgeon are also known to impact on plant community dynamics leading to algal blooms.


How might it get here? Escape from aquaria trade. Deliberate introduction as fish bait.


Prevent Spread:


  • Don’t dispose of aquaria material near a pond, river or waterbody.
  • Don’t introduce fish species.
  • Don’t introduce fish species from areas currently infested with TMG as the possibility of contamination is very high.

Invasive Species Ireland

Invasive Species Ireland