Australia’s rivers and lakes are as diverse as the landscapes they run through. From snow-fed alpine streams to vast inland billabongs, these waters hold truly iconic native fish such as Murray cod, barramundi and golden perch. But not every fish in these waters belongs here.
Since European settlement, dozens of exotic species have been released, both deliberately and accidentally. Some, like trout, are valued by anglers. Others, like carp and tilapia, are regarded as noxious pests. Together, they’ve reshaped ecosystems, challenged native fish and created a unique ‘feral fishery’ for Australian anglers.
This guide looks at the most common freshwater ferals, their history, impacts and most importantly – how and where you can catch them.
History and distribution
Carp were first brought to Australia in the 1800s as ornamental fish and a food source. Their big break came in the 1960s, when a strain known as the Boolarra carp escaped in Victoria and spread rapidly through the Murray–Darling Basin. Today, carp are entrenched across most of south-eastern Australia, making up as much as 90 per cent of fish biomass in some rivers.
Impact
Carp are bottom feeders. As they root through sediments, they muddy the water, uproot vegetation and reduce habitat quality for native fish and invertebrates. Their dominance is a major challenge for river health.
How, when and where to catch them
Carp are one of the easiest fish to target. They’ll take corn, bread, worms, dough, cheese and even artificial baits. Light lines, small hooks and a steady burley trail of breadcrumbs or corn often bring success. Shallow backwaters, billabongs and weedy river bends are prime spots. The best action comes in warmer months when carp cruise the shallows.
Can you eat them?
Carp’s reputation as a muddy, bony fish puts most anglers off. But in Europe and Asia they’re a prized food. If bled quickly and cooked creatively, smoked, curried or minced into patties, they can be surprisingly edible. At the very least, every carp removed is a win for the river.
History and distribution
While not truly considered ‘feral’, trout are not native to Australia. Brown trout were first introduced to Tasmania in 1864 when live ova were shipped from England. Rainbows arrived later, imported from North America via New Zealand in the 1890s. Brook trout came from North America too, though their distribution remains limited to select alpine lakes. Today, trout thrive in cool, clear waters of Tasmania, Victoria’s high country, New South Wales’ Snowy Mountains, and parts of South Australia and Western Australia.
Impact
Trout are a double-edged sword. They underpin thriving regional tourism and angling industries, but they also prey on and compete with native fish. Studies have highlighted their impact on small-bodied upland natives like galaxiids.
How, when and where to catch them
The best times are dawn and dusk when trout cruise the shallows, or evenings during insect hatches. In alpine lakes, summer sees trout patrolling windward shores for food. Winter brings spawning runs, which may be open or closed depending on state/territory rules – always check your local regulations.
Can you eat them?
Trout are superb table fish. Brown trout have a rich, earthy flavour, rainbows are milder and sweet, and brook trout are delicate. Grilled whole, smoked over a campfire or pan-fried in butter, they’re a favourite among anglers.
History and distribution
Brought from Europe in the 1860s, redfin, or English perch, are now widespread in southern Australia. They favour lakes, farm dams and slower rivers, particularly in Victoria, NSW, Tasmania, SA and WA.
Impact
Redfin are voracious predators, capable of wiping out entire populations of small native fish. They’re also carriers of EHN virus, which is lethal to natives like Murray cod and silver perch.
How, when and where to catch them
Redfin are an angler’s delight. They school around submerged timber, rocky outcrops and weed beds, striking at lures, soft plastics and worms. Dawn and dusk in autumn and spring bring the best bites. If you catch one, keep fishing the same spot – there are usually more.
Can you eat them?
Yes, redfin are excellent eating. Their firm, white flesh is perfect for pan-frying, grilling or deep-frying. Many anglers rate them as the best-tasting freshwater fish in southern Australia.
History and distribution
Native to Africa, tilapia were first brought to Australia in the 1970s through the aquarium trade. Illegal releases saw them establish in Queensland, particularly around Brisbane, Townsville and Cairns. They’ve since spread into northern NSW and parts of WA.
Impact
Tilapia are listed as noxious pests. They build nests, erode banks and outcompete native species. In Queensland, it’s illegal to return them to the water – you must kill them.
How, when and where to catch them
Tilapia are hardy and aggressive. They’ll take worms, bread and small lures. Warm, shallow lakes, weedy lagoons and slow-flowing creeks are hotspots. They often feed in schools, making for action-packed fishing.
Can you eat them?
Worldwide, tilapia are a major farmed species. Their mild flavour makes them versatile, often grilled, baked or in curries. In Australia, their pest status deters many anglers, but if handled properly they can be good table fare.
History and distribution
Australia’s feral goldfish are escapees from backyard ponds and aquariums. Released into creeks and rivers, they thrive in still and slow-moving waters across the country. Unlike their small ornamental cousins, wild goldfish grow over 40cm and weigh more than 2kg.
Impact
Goldfish may look harmless, but they uproot plants, stir sediment and compete with native fish. They also carry diseases and parasites.
How, when and where to catch them
Goldfish are rarely targeted, but they’ll take worms, corn and bread on light tackle. Urban creeks, farm dams and stillwater lagoons are the most likely places to encounter them.
Can you eat them?
Not recommended. Unlike carp or tilapia, goldfish are not considered a table fish. Their role in this story is as a reminder: never release aquarium fish into the wild.
Other freshwater pests
Beyond the main species, several smaller invaders also warrant mention:
Check your states for species lists. NSW, Vic, Qld, WA, SA, Tas, NT, ACT
The role of anglers
Introduced freshwater species present a mixed picture. Carp and tilapia are noxious pests, goldfish are unwanted hitchhikers, while trout and redfin have become embedded in angling culture.
What’s clear is that anglers have a role to play. By targeting these species responsibly, removing declared pests, and following state licence rules, you contribute to healthier waterways.
So next time you’re by a river, lake or alpine stream, think about chasing a feral. Whether it’s a rainbow trout sipping flies in a mountain creek, a feed of redfin fillets from a farm dam, or a carp hauled from the Murray, fishing for Australia’s freshwater outsiders offers both challenge and reward, while helping restore balance to our waterways.
Freshwater ferals may not belong here, but they’ve become part of the Australian fishing story. Want more stories like this? Pick up the latest issue of Great Australian Outdoors in our shop and keep exploring.
Photo credits: © Kagan Vainisi, some rights reserved (CC-BY-NC), © Kagan Vainisi, some rights reserved (CC-BY-NC), © Matthew John Rees, some rights reserved (CC-BY-NC), © Jake Orthman, some rights reserved (CC-BY-NC), © deborod inaturalist.org
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