Topmouth gudgeon

Pseudorasbora parva


Photo Credit: ©Matt Brazier - Environment Agency
Pseudorasbora parva
  • Well vegetated small channels, ponds and small lakes

  • 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.

Download N.I.E.A. ID guide

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.

  • 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 gudgeon 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.

Is it found in Northern Ireland?
  • It is not present in Northern Ireland.

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.
  • EU-level action includes a ban on sales and any planting or keeping, including in aquaria, as well as rapid eradication of any new populations to avoid the excessively high costs associated with its management later on.
  • Report all sightings.

You can help by reporting any sightings: @ the Centre for Environmental Data & Recording (CEDaR) - Or via the iRecord App.

Contacts/further information

Current Legislative Position (Listed on 03 August 2016)
  • This species must not intentionally be brought into the Union; kept; bred; transported to, from or within the United Kingdom, unless for the transportation to facilities in the context of eradication; placed on the market; used or exchanged; permitted to reproduce, grown or cultivated; or released into the environment.
For further queries, you can contact the Invasive Non Native Species (INNS) Team in the Northern Ireland Environment Agency on 028 9056 9558 or Email:

Species Related Files:

Invasive Species Northern Ireland

Invasive Species Northern Ireland