Freshwater Pests 

What impacts do freshwater pests have?

• Displacing our native fish – by competing with native fish for food and habitat, and by preying on native fish and their eggs.
• Spreading diseases - which may severely affect native fish and other aquatic life.
• Spreading parasites - either directly from exotic fish or indirectly via exotic aquarium plants that may carry animals such as water snails, which can harbour parasites.
• Altering and degrading natural habitat - by stirring up sediments, decreasing light attenuation, increasing nutrient loads, smothering other plants, or adding to bank destabilisation and erosion.

Exotic fresh-water fish such as Tilapia have the potential to severely impact on some commercial and recreational fisheries (e.g barramundi).

By altering native habitat and having the ability to out-compete native fish, exotic fish pose a serious threat to the biological diversity and unique Northern Territory ecosystems.

Don't release aquarium fish and aquatic plants into our waterways

The dumping of aquarium plants into waterways can cause extremely serious problems, with the potential for many exotic plants such as water hyacinth and salvinia to choke waterways, block drainage systems and impede navigation.

Give unwanted aquarium plants and animals to a pet shop, or dispose of them in a humane manner, such as by freezing. DO NOT release them (native or exotic) into local waterways or drains that feed into waterways.

What you can do to help

• Make sure backyard ponds are secure from overflowing in the Wet Season. Screen all outlets to prevent accidental escapes.
• Consider stocking ponds with native fish. Many native species such as gudgeons, rainbow fish, and spotted and delicate blue-eyes, offer better mosquito larvae control than exotics and are also frog-friendly (they don’t feed on native frog eggs and tadpoles).
• If you see any unusual fish or aquatic plants in waterways of the Northern Territory, please contact the Aquatic Biosecurity unit immediately with details and if possible collect a sample of the plant or fish.

Alerts

• Exotic Aquatic Snails in the Northern Territory
• American Ribbed Fluke Snail [ Pseudosuccinea columella]
• Tilapia - A Rising Threat
• Have you seen these exotic Fish?