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Exotic pest fish - Non-indigenous fish

What is a non-indigenous fish?

A non-indigenous fish is one that is living in an area where it is not naturally found.  A non-indigenous fish may be a fish from another country, state/territory or catchment.  For example, a fish that is naturally found in the northern part of Queensland (eg banded grunter) would be classed as non-indigenous if it was found in waterways in south-east Queensland. 

How are non-indigenous fish introduced?

Non-indigenous fish are introduced to our waterways through the following methods:

• People dumping aquarium fish into creeks and ponds (eg goldfish, sailfin mollies, guppies, platies);
• Introduced as sportfish (eg carp, salmon, perch, trout);
• People using fish from other catchments as live bait;
• People stocking the wrong fish for their area into dams and ponds which overflow into other waterways.

Have any non-indigenous fish established in Queensland waterways?

Yes.  Go to non-indigenous fish (species information) to read about which fish from other countries have established populations in Queensland waterways.

Fish that are native to Queensland, but have established beyond their natural or stocked range are:

• Redlcaw crayfish:  These are naturally found in the Gulf of Carpentaria drainage division and from the Jacky Jacky River basin south to the Normanby River basin on the east coast of Queensland.  Due to people using them as bait and stocking them into dams outside this range, they have established populations in several waterbodies in Queensland.
• Sooty grunter:  Sooty grunter naturally occur in the coastal rivers north of and including the Burdekin River, Gulf of Carpentaria and west to the Daly River in the Northern Territory.  They have also been stocked into many northern Queensland dams.  Sooty grunters have been found in the Mary River cathchment.  There is concern that they will impact on Mary River Cod which are threatened.

What damage can non-indigenous fish do?

The introduction of non-indigenous fish often leads to the reduction of native fish. This is because the non-indigenous fish compete with native fish for food and space.  They may also be aggressive, cause habitat disturbance and introduce diseases which the native fish are not used to.

The introduction of fish into other waterways may also introduce exotic parasites and diseases. Goldfish ulcer disease is believed to have entered Australia via the aquarium trade and has rapidly spread to wild goldfish stocks.

Why are non-indigenous fish so successful?

Non-indigenous fish that have successfully invaded Australian waters have one or more of the following attributes:

• wide environmental tolerances;
• flexible food requirements;
• high reproductive output;
• early maturation;
• aggressive behaviour
• lack of predators and competitors.

Introduced fish often inhabit and flourish in disturbed waterways (such as stagnant creeks, drains) as these often have abundant food resources and lack native fishes because of harsh and changed environmental conditions.

How can I prevent non-indigenous fish being introduced to our waterways?

• Farm dams often overflow into rivers and creeks during times of high rainfall. Unless you have a permit to do so, it is an offence to stock your farm dam with fish that do not occur naturally in your area.  Stocking the wrong fish in your dam may lead to irreversible changes to local fish populations if the fish escape from your dam during floods.  See native fish as alternatives to exotic fish  to see which fish can be stocked into your farm dam.
• Ornamental ponds are attractive features in gardens.  People often put goldfish or other non-indigenous fish in them.  This is allowed, as long as they don't escape during high rainfall.  A better alternative would be to put native fish in your pond.  Native fish are great for ponds as they are good for mosquito control, have interesting colours and shapes and some of the larger species have their own "personality".   See native fish as alternatives to exotic fish  to see what native fish are great for your garden pond.
• Never dump your aquarium contents into waterways.  Never flush them down the toilet either, as the water will eventually end up in our waterways.  If you no longer want fish that are in your aquarium, see if your local pet shop will take them off you.  If not, you should kill them humanely by placing them in an ice slurry (mixture of ice and cold water).  This will slow their metabolism and make them go to sleep. 
• Do not use transport fish between catchments to use as bait.  Live bait may escape and dead bait may have viable eggs. 

What should I do if I find a non-indigenous fish?

If you find a fish that is not native to the area,  call the DPI&F Call Centre on 13 25 23 to report it.

If you catch a non-indigenous fish in the wild, you should kill it and dispose of it.  Do not return it back to the water.  This also applies to fish that are regulated in Queensland, but not native to the catchment.  For example, sooty grunter have a regulated minimum size limit of 28cm in their endemic and stocked range, but are not protected in areas where they are non-indigenous (eg Mary River catchment). 

What is the natural range of Queensland freshwater species?

To find out the natural range of Queensland freshwater species, click on the relevant fish below.

Australian bass
Barcoo grunter
Barramundi
Eel-tailed catfish
Freshwater eel
Golden perch (yellowbelly)
Jungle perch
Lungfish
Mary River cod
Murray cod
Northern saratoga
Redclaw
Silver perch
Sooty grunter
Southern saratoga

How do you remove non-indigenous fish once they have established?

Once a fish has established in a waterway, it is very difficult if not impossible, to remove them.  It is therefore much better to prevent their introduction and/or spread by educating people about the negative impacts of introduced fish.

Legislation

Some non-indigenous fish from other countries can be kept in Queensland without a permit as long as they cannot escape (eg in an aquarium or in a pond that will not overflow).  For a complete listing of allowable non-indigenous fish, please see Non-indigenous fish - prescribed list.

It is an offence to release or cause non-indigenous fish to be released (eg pond or dam overflowing) into Queensland water.  Fines of up to $150 000 apply. Additional penalties may be imposed for eradication measures.

Please refer to the  Fisheries Act 1994 and Fisheries Regulation 2008 for as a complete reference to fisheries legislation.  Copies of legislation can be dowloaded directly at the Office of Parliamentary Counsel website.

Last updated 1 April 2008