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Platy (Xiphophorus maculatus)

Platies are introduced ornamental fish that are established in Australia. They can compete with native fish for food and, as prolific breeders, may rapidly outnumber native fish and dominate habitats.

Key facts

Type: Pest animal, fish.

Native to: Atlantic-slope Central America, from southern Mexico to Belize.

Established in: QLD, NT.

Other names: Southern platyfish.

Best time to act: Survey during warmer months, when fish are more active and easier to detect.

Identification

  • A small-bodied livebearing fish, with females growing up to 6 cm and males up to 4 cm.
  • Domesticated fish are commonly orange with black markings; escaped or released fish may be olive-brown with blue-green markings.
  • Males have an extended anal fin, modified into a reproductive organ, and females are generally larger.
  • Females mature at around 12–16 weeks and produce 20–100 live young per cycle, with cycles occurring every four to six weeks.
  • Look-alike: Platies may be confused with other small ornamental livebearers, including guppies and mollies.

Where it lives

In Australia, platies may be found in freshwater waterways and other waterbodies where ornamental fish have been released or have escaped from ponds.

Why it matters

  • They can compete with native fish for food.
  • Prolific breeding can allow them to rapidly outnumber native fish and dominate habitats.

How it spreads

  • Platies can enter waterways when unwanted aquarium fish are released.
  • They may also escape from backyard ponds or other stocked waterbodies.

Control methods

  • Confirm identification and report sightings to the relevant state or territory fisheries or biosecurity authority for advice on approved management options.
  • Where authorised, use targeted nets or traps to remove fish, and handle and dispatch captured fish humanely.
  • Do not release captured fish or transport live fish or water to another waterbody.
  • Repeat surveys and removal as advised by the relevant authority to check for remaining fish.

Site hygiene and welfare

  • Contain captured fish and water, and never empty aquarium or pond water into waterways.
  • Before moving between waterbodies, drain, clean and dry boats, nets, boots and other equipment.
  • 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: General biosecurity duty. Not prohibited matter in NSW. The general biosecurity duty applies: anyone dealing with it must prevent, eliminate or minimise the risk it poses.
  • Victoria: Not declared. Not declared under the Catchment and Land Protection Act 1994. Other Victorian laws may still apply.
  • South Australia: Not declared. Not declared under the Landscape South Australia Act 2019. Other laws may still apply.
  • Western Australia: Not listed. Not found in the Western Australian Organism List. Check with DPIRD before moving or keeping it.
  • Tasmania: Not a declared pest. Not a declared pest or prohibited matter in Tasmania. Importing animals is still controlled by Biosecurity Tasmania.
  • 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.

  • Queensland: Biosecurity Act 2014 (Qld), administered by Biosecurity Queensland (13 25 23)
  • Northern Territory: Territory Parks and Wildlife Conservation Act 1976 (NT), administered by NT Department of Lands, Planning and Environment

Sources