What should you do if you catch a tilapia?
Tilapia are one of the most problematic invasive fish species in Townsville's waterways.
If you catch a tilapia, you should:
Humanely kill the fish. The most appropriate way may be to stun it with a sharp blow to the back of the head, just above the eyes.
Dispose of it responsibly — away from the water. Bury the dead fish well away from the water's edge or above the high tide mark, or dispose of it in a general rubbish bin.
Never release it into a waterway. Don’t keep it. Don’t feed it. Don’t sell it or give it away.
Female tilapia are mouth brooders, meaning they carry eggs in their mouths. The eggs can survive for some time after the adult fish dies, making responsible disposal critical.
Tilapia are highly adaptable to different environmental conditions and breed rapidly, allowing them to establish large populations.
They compete with native fish for food and shelter, prey on eggs and juvenile fish, and can further degrade habitats already under stress.
Tilapia are classified as restricted noxious fish under Queensland's Biosecurity Act 2014. Penalties may apply if you keep, feed, give away, sell, or release them into the environment.
How to report a sighting
Community reporting helps biosecurity agencies detect new outbreaks early, before invasive populations become established.
You can report tilapia sightings to Biosecurity Queensland if you suspect a new outbreak.
Tilapia are already well-established in Townsville's Black and Ross Rivers, so sightings in these waterways do not need to be reported.
An aquarium fish gone feral
One of the biggest challenges in managing tilapia is stopping them from spreading into new waterways. Unfortunately, these invasive fish sometimes get a helping hand.
The species first arrived in Australia through the aquarium trade in the 1970s. Over time, unwanted fish have been released into creeks and rivers, or sent down the drain, where they established wild populations.
In Townsville, stories persist of small tilapia being caught in the Palmetum and used as bait in the Ross River. While it may seem harmless, giving the pest a free ride into another waterway can have serious consequences.
We're keeping watch on our waterways
The annual Townsville Dry Tropics Waterways Report Card helps track the health of our freshwater ecosystems by monitoring the balance between native and introduced fish species. Healthy waterways tend to support a diverse range of native fish, while waterways under pressure are often dominated by fewer, non-native species.
The 2026 Report Card found that tilapia were present at more than half the fish monitoring sites across the region, highlighting the ongoing threat to native fish populations. By tracking fish health over time, the Report Card helps identify waterways under pressure and provides valuable information to support local waterway management.
We work with partners to promote the health of our local waterways, including events such as the Tilapia Takedown. See the latest event action here.
