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Redbelly tilapia (Coptodon zillii)

Redbelly tilapia is an introduced fish that can establish in warm Australian waterways and compete with native fish. Its grazing on aquatic plants can damage habitat and undermine aquatic vegetation restoration.

Key facts

Type: Pest animal, fish.

Native to: Africa and the Middle East.

Established in: .

Other names: Zill's tilapia, Zille's cichlid, Redbelly cichlid, Tilapia zillii.

Best time to act: Survey year-round in warm regions, paying particular attention to shallow vegetated margins where fish feed and nest.

Identification

  • It has a deep, laterally compressed body and a blunt head.
  • Adults are usually olive or greenish, with dark vertical bars or blotches along the sides.
  • Blue-green spots may be visible on the scales and fins.
  • The belly and breast can be red or orange, especially in breeding fish.
  • It has a long dorsal fin with a spiny front section and a rounded tail.
  • Look-alike: It can be confused with other introduced tilapias, including Mozambique tilapia; colour alone is not a reliable basis for identification.

Where it lives

In Australia it can live in warm freshwater rivers, lakes, ponds and reservoirs, including shallow areas with aquatic vegetation.

Why it matters

  • It feeds heavily on aquatic plants, potentially reducing submerged vegetation and the habitat and shelter it provides.
  • Loss of aquatic vegetation can disrupt restoration work and affect water quality.
  • It can compete with native fish for food and habitat.

How it spreads

  • People can spread it by releasing or moving live fish, including from ponds or aquariums.
  • Once present, it can spread through connected waterways and may disperse when waterways flood.

Control methods

  • Confirm identification and contact the relevant state or territory biosecurity agency for local advice and reporting requirements.
  • Use targeted netting, trapping or other approved physical removal methods, with suitably trained crews and care to minimise harm to native fish.
  • Do not release captured fish or move live fish or water between water bodies; dispose of captured fish as directed by local authorities.
  • Repeat surveys and removal after treatment, and use chemical control only where specifically approved by the relevant authorities.

Site hygiene and welfare

  • Before moving between water bodies, drain water from boats, buckets and fishing gear, and clean and dry equipment.
  • Remove aquatic plant material and any fish from nets and gear, and do not transfer them 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: Not prohibited or restricted. Not listed as prohibited or restricted matter in Queensland. 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: Not listed. Not found in the Western Australian Organism List. Check with DPIRD before moving or keeping it.
  • 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: Not declared. Not declared under the Biosecurity Act 2023 (ACT). A general biosecurity duty still applies.

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.

Sources