Tilapia

Introduction

Tilapia are listed in the top 100 of the world’s worst introduced species and are a Class 1 noxious fish in all waters of NSW under the Fisheries Management Act 1994. Possession and sale of live tilapia is prohibited with penalties of: up to $11,000 for possession; and up to $55,000 for sale. Release of tilapia can also carry penalties of up to $55,000. Tilapia pose a significant threat to native fish species and aquatic habitats of NSW. The greatest risk for the spread of tilapia is by humans, whether deliberate or accidental - this means you can help stop the spread of this noxious pest fish.

Why are tilapia a risk to native fish and habitats?

Characteristics allow tilapia to establish in new areas include:

  • highly efficient breeding strategies including mouth brooding
  • simple food requirements (feeding on a wide variety of plant and animal matter)
  • flexible habitat preferences (including the ability to breed in both fresh and brackish water).

Impacts tilapia have on native fish and habitats include:

  • competition with native species for food and space
  • predation upon the eggs and young of native species
  • aggressive behaviour of tilapia can lead to poor condition and higher infection and mortality rates for native species
  • nest building by male tilapia may also damage aquatic habitats through damage to aquatic vegetation and increased turbidity.

Where are tilapia found in NSW and elsewhere in Australia?

In December 2014, NSW Department of Primary Industries confirmed that a population of the tilapia species, Mozambique Tilapia (Oreochromis mossambicus), had established at Cabarita Beach on the NSW far north coast. This is the first confirmed population of tilapia in NSW. Three species of tilapia - Mozambique Tilapia (Oreochromis mossambicus), Spotted Tilapia (Tilapia mariae) and Redbelly Tilapia (Tilapia zillii) - have established successful breeding populations at several sites in Queensland, Victoria and Western Australia. Populations of Mozambique Tilapia within southern Queensland are as little as 3 km from the Murray-Darling Basin (MDB). Tilapia pose a significant threat to the native fish of the MDB. For more information on the distribution of tilapia in Australia, see Species of tilapia found in Australian waters.

Where did tilapia come from and how did they get here?

Tilapia are native to warm, fresh and brackish waters of Africa, South and Central America, southern India and Sri Lanka. Approximately 150 species have been imported into Australia, primarily for use as aquarium fish.

What is the government doing to help stop the spread of tilapia?

NSW DPI works with other government agencies, non-government agencies, industry and the community to minimise the risks of tilapia spreading and establishing throughout NSW. This approach recognises that biosecurity is a shared responsibility.

NSW DPI:

  • maintains legislation regarding noxious species such as tilapia
  • monitors fish populations in coastal and inland rivers in NSW
  • prepare for potential incursions of noxious species
  • responds to reported sightings of noxious species, including tilapia
  • works to raise awareness of noxious species (e.g. advisory materials, workshops, media releases).

How you can help stop the spread of tilapia

Tilapia infestations are usually caused by people moving the fish between waterways. Help stop this spread with the following guidelines:

  • Don’t release fish into waters or allow fish to escape into waterways.
  • Don’t use suspected pest species as bait (whether dead or alive). Even dead tilapia may still have eggs or young in their mouths.
  • Obtain a permit from NSW DPI prior to any fish stocking activities and stock fish from a reputable local supplier rather than another region or interstate (to minimise risks of introducing species not native to your local area). Note - it is illegal to release fish into waters without a permit and heavy penalties apply.
  • Give unwanted aquarium fish to a friend or a pet shop. If a suitable home cannot be found, please see the recommended guidelines for humane destruction of fish.
  • Learn how to identify tilapia.
  • Be on the lookout for new species of fish in your area.
  • Report sightings of suspected tilapia, take good quality photographs and freeze the whole fish where possible.
  • Clean your gear (e.g. landing nets, boots) and check for signs of eggs or young tilapia. If found, ensure these eggs and young are not able to re-enter any NSW waters.

How to identify tilapia

  • Tilapia vary in colour from dark olive to silver-grey, depending on their age and environment.
  • They are generally deep-bodied fish with thin profiles, long snouts and pronounced lips/jaws.
  • Their dorsal (upper) fin (1) is continuous and ends in an extended point. Most native species have a dorsal fin with a dent/gap in the middle and a rounded end.
  • Their pelvic (belly) fins (2) are long and almost touch the front of the anal (bottom) fin (3). This is unlike most native species, which have short pelvic fins.
Diagram of tilapia

Diagram of tilapia

Other fish species that tilapia are often confused with include:

  • Banded Grunter (Amniataba percoides)
  • Bream (Acanthopagrus spp.)
  • Juvenile Silver Perch (Bidyanus bidyanus)

Species of tilapia found in Australian waters

Mozambique Tilapia

Mozambique tilapia

Mozambique Tilapia - Oreochromis mossambicus.
Photo: Qld DAF

Of all the tilapia species, the Mozambique Tilapia (Oreochromis mossambicus) has the most widely distributed feral populations in Australia. In December 2014, NSW DPI confirmed that this species had established a population at Cabarita Beach on the NSW far north coast. It is also the species of tilapia most at risk of entering the Murray-Darling Basin, with populations as little as 3 km from this river system in southern Queensland. Mozambique Tilapia have established several breeding populations in northern and southern Queensland, including Brisbane, Townsville and Cairns. They have also become established north of Geraldton in Western Australia.

Mozambique Tilapia can grow to more than 36 cm in length and live for up to 13 years. However, size varies according to environmental conditions, with poor conditions sometimes producing many small (but still mature) fish.

Male Mozambique Tilapia with red edging on its fins

Male Mozambique Tilapia with red edging on its fins.
Photo: Qld DAF

Tilapia can become sexually mature less than one year in ideal conditions. This equates to a fish around 15 cm long, although stunted fish can breed at 9 cm. Breeding males become very dark (almost black) with red edging on their fins.

After spawning, the female takes the eggs in her mouth, where they hatch - the fry remain in their mother's mouth for up to 14 days before they are released, and may remain near the mother and re-enter the mouth when threatened until about three weeks old, thus receiving protection from predators. This strategy is known as mouth brooding.

Mozambique Tilapia are hardy fish, tolerating a wide range of temperatures and surviving in high salinities and low dissolved oxygen. Consequently they have colonised a variety of habitats including reservoirs, lakes, ponds, rivers, creeks, drains, swamps and tidal creeks. They usually live in mud bottomed, well-vegetated areas, and are often seen in loose aggregations or small schools.

Mozambique Tilapia with eggs

Mozambique Tilapia can protect eggs and larvae in their mouth for up to 14 days.
Photo: Qld DAF

Spotted Tilapia

Spotted Tilapia

Spotted Tilapia - Tilapia mariae.
Photo: Gunther Schmida

Spotted Tilapia (Tilapia mariae), also known as Black Mangrove Cichlids, are found in northern Queensland waters around the Cairns region. They have also established a self-sustaining population in the heated waters of the Hazelwood power station pondage near Morwell in Victoria.

Spotted Tilapia grow to around 30 cm in length. They become sexually mature at about 10 to 15 cm. They prefer to spawn on hard substrates (such as logs), which they clean beforehand. They do not build nests and are not mouth brooders, but the eggs and fry are carefully guarded by one or both parents. The parents continue to care for the young until they are about 2-3 cm.

Spotted Tilapia are less tolerant of cooler temperatures than Mozambique Tilapia.

Their diet consists mainly of plants, although it appears they also eat animals when there is limited aquatic vegetation available.

Redbelly Tilapia

Redbelly Tilapia

Redbelly Tilapia - Tilapia zillii.
Photo: Gunther Schmida

Redbelly Tilapia (Tilapia zillii), also known as Zille’s cichlid, are another species considered to be a potential threat if introduced into NSW waterways. An outbreak of Redbelly Tilapia occurred near Perth in Western Australia in 1975, but was eradicated by the state fisheries department.

They are normally found in sheltered waters over rock, sand or mud, including shallow pools, lagoons and the margins of rivers.

Commonly misidentified species

Banded Grunter

Banded Grunter

Juvenile Banded Grunter (top) and juvenile Mozambique Tilapia (bottom).
Photo: Qld DAF

The major differences between Banded Grunter (Amniataba percoides), also known as Barred Grunter, and tilapia include:

  • Banded Grunter have a dent separating the front of the dorsal (upper) fin from the back of the fin
  • The end of the dorsal (upper) fin on a Banded Grunter is rounded

Please note that Banded Grunter are listed as a Class 2 noxious fish in all waters of NSW.

Bream

Yellowfin Bream
Mozambique Tilapia similar to Yellowfin Bream

Juvenile Banded Grunter (top) and juvenile Mozambique Tilapia (bottom).
Photo: Qld DAF

The major differences between Bream (Acanthopagrus spp.) and tilapia include:

  • Bream have a forked caudal (tail) fin
  • The end of the dorsal (upper) fin on Bream is rounded.

Juvenile Silver Perch

Juvenile Silver Perch

Juvenile Silver Perch.
Photo: Dean Gilligan

The major differences between Juvenile Silver Perch and tilapia include:

  • Juvenile Silver Perch have a longer, skinnier body shape
  • Silver Perch have a dent separating the front of the dorsal (upper) fin from the back of this fin
  • The end of the dorsal (upper) fin on a Silver Perch is rounded
  • Silver Perch have a forked caudal (tail) fin.

References

Allen GR, Midgley SH, Allen M. (2002). Freshwater Fishes of Australia. Western Australian Museum, Perth.

Arthington AH, Bluhdorn DR. (1994). Distribution, genetics, ecology and status of the introduced cichlid, Oreochromis mossambicus, in Australia. Internationale Vereinigung fur theoretische und angewandte Limnologie/Communications 24: 53-62.

Condamine Alliance. 2014. Implementing the Northern Murray-Darling Basin Tilapia Exclusion Strategy – Final Report.Project to Murray-Darling Basin Authority, Queensland.

Hutchison M., Safac Z., and Norris A – Department of Employment, Economic Development and Innovation [2011]. Mozambique tilapia. The potential for Mozambique tilapia Oreochromis mossambicus to invade the Murray-Darling Basin and the likely impacts: a review of existing information. Murray-Darling Basin Authority under a Creative Commons Attribution 3.0 Australia Licence.

Lever C. (1996). Naturalized Fishes of the World. Academic Press, San Diego.

McDowall R. (Ed) (1996). Freshwater Fishes of South-Eastern Australia. Reed Books, Australia.