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Roach (Rutilus rutilus)

Roach was introduced to Australia from the United Kingdom in the 19th century as forage fish. It can compete with native species, hybridise with related fish and alter food webs, so suspected populations should be identified and managed carefully.

Key facts

Type: Pest animal, fish.

Native to: Eurasia, from Europe and the Aegean region east through the Ural and Aral basins into Siberia..

Established in: VIC.

Other names: Common roach, European roach.

Identification

  • A deep-bodied, laterally compressed fish with a forked tail and a pointed snout.
  • Adults can reach 50 cm, though the average reported size is about 25 cm.
  • It has 39–48 scales along the lateral line and no dark stripe along the side.
  • The iris is yellow in juveniles and deep red in adults; the pectoral, pelvic and anal fins are orange to red.
  • Juveniles can be difficult to identify, and confirming an identification may require examining several physical features or genetic testing.
  • Look-alike: Roach may be confused with other cyprinid fishes, including rudd; hybrids with rudd and bream are also reported.

Where it lives

It inhabits lowland freshwater lakes, large and medium-sized rivers, backwaters and other slow-flowing or sheltered waters, and may use brackish water.

Why it matters

  • Roach can compete with native fish for food and other resources, and can hybridise with related species such as rudd and bream.
  • In lakes, abundant roach can consume large amounts of zooplankton and contribute to a shift towards turbid, nutrient-enriched conditions.
  • Roach has been reported to compete with tufted ducks for benthic food.

How it spreads

  • Roach has been moved intentionally between waters for angling and as forage fish, and has also been transported as live bait.
  • Fish can spread through connected waterways, including where water is diverted or fish escape from lakes.
  • Weirs and dams can create sheltered, lake-like habitat that favours roach.

Control methods

  • Do not release or transfer roach, including as live bait, and do not move fish between water bodies.
  • Where removal is appropriate, use authorised physical methods such as nets or electrofishing, with trained crews and in accordance with state or territory requirements.
  • Barriers or rotenone may be considered for small fish populations only where approved and permitted by the relevant authorities.
  • Monitor treated waters for survivors and new occurrences, and report suspected roach to the state or territory biosecurity or fisheries agency.

Site hygiene and welfare

  • Do not transport live fish or water between sites; drain boats and equipment before leaving the water.
  • Clean and dry boats, nets, footwear and other gear before moving to another waterway.
  • Use methods set out in the national model codes of practice and standard operating procedures for the species.
  • Coordinate control with neighbours and the local government biosecurity plan, as isolated effort is quickly undone by reinvasion.

Classification by state

  • Australia (national): No national listing. Managed under state and territory law.
  • Queensland: Prohibited matter. Report it to Biosecurity Queensland on 13 25 23 within 24 hours and do not move or deal with it. Everyone must also take all reasonable and practical steps to minimise its risks (the general biosecurity obligation).
  • New South Wales: Prohibited matter. It is an offence to deal with it, and you must notify NSW DPIRD as soon as you become aware of it.
  • Victoria: Not declared. Not declared under the Catchment and Land Protection Act 1994. Other Victorian laws may still apply.
  • South Australia: Noxious species. Declared a noxious species under the Fisheries Management Act 2007, so it must not be brought into South Australia, kept, sold or released, and it must not be returned to the water alive. Report any sighting to PIRSA FISHWATCH on 1800 065 522.
  • Western Australia: Noxious fish. Prescribed as a noxious fish under the Fish Resources Management Regulations 1995, so it must not be brought into WA, kept, sold or released. Report any sighting to FishWatch on 1800 815 507.
  • Tasmania: Declared pest. It is a declared pest under the Biosecurity Act 2019 (Tas). Report sightings to Biosecurity Tasmania and follow any management requirements.
  • Northern Territory: Not a declared pest. Not on an NT declared or prohibited list. Check with the NT Government before keeping, moving or releasing it.
  • Australian Capital Territory: Declared pest, prohibited. It is a declared pest throughout the ACT. Dealing with it, such as selling, moving or keeping it, is prohibited.

Legal obligations

Every state and territory places a duty on landholders and people working on land to prevent the spread of invasive species, such as the general biosecurity obligation in Queensland and the general biosecurity duty in New South Wales. Declarations and control requirements differ between states and local government areas, so check the current official list before work starts.

  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria

Sources