A NEW threat is facing local water ways.

While carp may have well and truly taken over habitats and be competing for the resources of native fish, Tilapia is also on its way.

Department of Employment, Economic Development and Innovation Pest Fish officer Danielle Stewart said over 200 people turned out to catch a carp at the weekend, but Tilapia was the talk of the day.

"It's really about education and getting people together and raising awareness about pest fish," she said.

"And Tilapia is the newest threat."

Included in the world's 100 worst invasive species, Ms Stewart said the mouth-brooding fish had not reached the waters of the Murray-Darling yet - but it was close.

"And once they are there, there is nothing we can do about them," she said.

"It has been present in the Brisbane River for 10 years and has been identified as living in the Lockyer Valley and the upper Burnett region."

Also known as the Mozambique mouth-brooder, Ms Stewart said Tilapia was one of the most eaten fish in the world - which meant they posed an even bigger threat.

"People will say, 'oh I have eaten that in the Philippines,' and then come back and see it and bring it back to their local waterways," she said.

The prolific breeders can reproduce all year around.

They are omnivores, so have highly adaptable food requirements. They could also adapt to a variety of habitats and would quickly dominate a water body, out-competing native fish.

Ms Stewart said there were steps people could to take to try and stem the spread of the fish into the Murray-Darling Basin but the biggest problem was that people often didn't even realise they were spreading them.

What you need to know about the Tilapia:

Tilapia varies in colour from dark to 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 fin is continuous and ends in an extended point.

Their pelvic fibs are long and almost touch the front of the anal fin.

Infestations are usually caused by people moving between waterways.

Don't use Tilapia as bait - dead or alive.

Don't empty aquariums on local water ways.

Don't stock dams or ponds with them - use native fish instead.

Don't return a catch of Tilapia to the water - if you catch them, kill them humanely and either bury them or put them in a bin.

If you catch or sight a Tilapia, report it.

Record the date, location, description of the fish (photograph if possible) and a description of the water way.

Call 13 25 23 or visit www.fisheries.qld.gov.au.