A NSW Government website

Choosing which fish to keep

Native fish

Native fish can be an attractive and interesting alternative to keeping non-native fish in aquaria. A large variety of species can be obtained from aquarium shops, native plant nurseries or water garden suppliers (NB: native fish cannot be collected from the wild to keep in ponds or aquaria without a specific permit). Whilst native fish are encouraged as a preferable option for  fish hobbyists , care should still be taken to prevent release of into the wild, as they can also have an impact on local populations. Species that occur naturally in other parts of Australia may cause problems if introduced into an area outside their natural range (e.g. banded grunter (Amniataba percoides) and Caulerpa taxifolia, a pest marine vegetation).

Non-native species

Non-native fish species, whilst popular to keep, can cause significant damage if released into natural waterways. Two species that illustrate the impacts of non-native fish introduction are eastern gambusia and carp. Gambusia is now listed as a 'key threatening process' by the Office of Environment and Heritage because of their impacts on native frogs.

Other non-native aquarium species to take particular care of include the groups below. Some have already become pests and pose a threat to our rivers and oceans.

Two gambusia holbrooki fish, one large and the other smaller 

Livebearer family

Includes guppies, mollies, and ‘mosquitofish’. Two species (gambusia  and one spot livebearer/speckled mosquitofish) are aggressive pests with most species banned from sale in NSW (excludes Eastern gambusia).

Yellow cichlid sitting on the bottom of a tank part hidden by gravel 


A popular and very diverse group of aquarium fish, but some species have established pest populations (e.g. Jack Dempsey (eight banded) cichlid and pearl cichlid). Tilapia are banned in NSW.

White cloud mountain minnow - two small fish in a tank 

Carp & minnow family

Includes minnows, bitterlings, danios, and rasboras. Five species (carpgoldfish, roach, tench and white cloud mountain minnow) are pests in NSW. Some – like carp – are major pests.

Long skinny speckled grey fish laying on gravel 

Loach family

These non-natives are very hardy and can move overland to invade new areas. Oriental weatherloach has established pest populations.

An aquatic plant in a tank with gravel 

Marine & freshwater weeds

Assume that all aquatic plants in your aquarium or pond are potential weeds. Some (e.g. salviniacabomba and alligator weed) have already invaded NSW waterways, and are totally banned.

Two yellow aquarium snails on a blank background with strands of aquatic weed.  


Fresh and saltwater snails can be big vegetation eaters. Keep them safe in your aquarium.

Live rock in an aquarium with a couple of tropical fish  

‘Live rock’

‘Live rock’ (used in marine aquariums) contains all kinds of tiny animals and should never be dumped in or near the sea.

Freshwater finfish pests

While several freshwater pest fish species have long term established populations in NSW, there's been an increase in ornamental fish species reported as established in the wild. These ornamental pest fish introductions are believed to occur through both accidental and intentional release. Some may have been released by owners that no longer want the fish but were unaware of the options available for appropriate disposal, humane destruction of fish, and environmental consequences of release.