Longfin Eel

The biggest freshwater eel in Australia can spend more than fifty years in a river, hunting after dark, before it swims to the Coral Sea to spawn once and die.

Family

Anguillidae

Origin

Native

How to tell it

The longfin eel is the largest freshwater eel in Australia, NSW DPIRD says, and the females grow much bigger than the males. It is a thick, mottled, olive-and-brown animal with a small eye and a wide mouth, and Fishes of Australia calls it the top predator in many of the waters it lives in. Anyone who has fished the coastal rivers of the east at night has probably lost tackle to one.

Its life runs on a longer clock than any fish you will catch on a fly. Fishes of Australia says adults may stay in fresh water for more than 50 years before they migrate to the Coral Sea to spawn below 400 metres. The young come back as transparent glass eels, colour up as elvers in the estuaries and push upstream into rivers, swamps and lakes, as far up as the headwaters.

NSW DPIRD calls it a good recreational species because of its size and strength. It is not a fly fishery and this page does not pretend it is, but eels do hit streamers, and an angler who fishes big flies after dark in eel country should know what has just bent the rod.

The quick read

A large, mottled, night-feeding eel of coastal rivers from Cape York to Melbourne and the north and east of Tasmania. It prefers flowing water but turns up in lakes, swamps and reservoirs. It eats fish, crustaceans, molluscs and insects, and occasionally young waterfowl. Most are caught on bait at night. It can be kept under bag and size limits in Victoria, Tasmania and Queensland. Tell it from the shortfin by its mottling and by where the back fin begins.

Range in Australia

Fishes of Australia gives the range as the coastal drainages of eastern Australia from Cape York to Melbourne, northern and eastern Tasmania, and Lord Howe Island. NSW DPIRD describes it on the coastal side of the Great Dividing Range, in rivers, streams, dams, lagoons and lakes, from Cape York south through New South Wales into Victoria and Tasmania. In Tasmania, the Inland Fisheries Service calls it reasonably common in coastal streams and swamps on the north and east coasts, and names large in-stream barriers, including hydro dams, as a block on its upstream migration.

In this guide the species is recorded in the Snowy River, with records from 1974 to 2024, and in the South Esk River in 2001. Those are records of the eel being found, not a fishery for it.

Habitat and behaviour

Fishes of Australia says longfins prefer flowing water and commonly live in rivers from the mouth to the headwater streams, as well as lakes, swamps, floodplains and deep reservoirs. The Inland Fisheries Service, describing Tasmanian fish, says it is less common in lakes than the shortfin.

It hunts at night. Fishes of Australia says it usually feeds after dark on fish, crustaceans, molluscs and insects, and occasionally juvenile waterfowl, which the Inland Fisheries Service also notes.

On size, Fishes of Australia says longfins commonly reach 100 to 150 centimetres and 1 to 2 kilograms, that males stay small, around 65 centimetres and 600 grams, and that landlocked eels prevented from migrating can reach 3 metres and 22 kilograms. The Inland Fisheries Service gives a common size of about a metre in Tasmania, with fish reaching 3 metres and more than 20 kilograms.

Confusing species

The shortfin eel overlaps with the longfin in Victoria, New South Wales and Tasmania. Check two things:

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Colour. The longfin is mottled or marbled: Fishes of Australia describes olive-green to brown markings over a paler underside, and the Inland Fisheries Service a mottled or spotted back and sides. The Australian Museum says the shortfin is the only freshwater eel in southern Australia with a uniform body colour.

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The back fin. On a longfin the dorsal fin begins well forward of the anal fin; Fishes of Australia puts its origin well in front of a line through the vent. On a shortfin, the Inland Fisheries Service says it starts about level with, or just in front of, the anal fin.

A silver longfin heading for the sea is a different colour again: Fishes of Australia describes migrating adults as silvery overall, with a mottled underside and often yellowish pectoral fins. A freshwater catfish also has an eel-like tail, but it has barbels around its mouth.

Fishing for them

Bait at night is the standard method. NSW DPIRD says longfins are commonly caught at night on baited hooks, particularly pieces of fish and earthworms.

On fly, the evidence is anecdotal but real. On the Orvis fly fishing podcast, the Australian guide Angus Reynolds, who mostly guides for trout, describes casting a large streamer into a waterfall pool for trout or cod, hooking big eels instead, and going on to catch eels deliberately on an eight-weight rod in other waters. He does not name the species. If you want to try the same approach on a longfin:

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Rod and leader: an eight weight is not too heavy for a big eel, with a stout leader, because a hooked eel heads for the nearest rock or root.

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Flies: a large, bulky streamer fished low and slow after dark. A big Woolly Bugger or a Muddler Minnow imitating a small fish is a reasonable start.

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Where: deep, slow pools and the bottoms of runs, especially below falls and around cover, after dark. See streamer fishing for the retrieve, and the Murray cod timber notes for fishing big flies around snags.

Expect a longfin to be a by-catch more often than a target.

Spawning season

There is none in fresh water. The Inland Fisheries Service explains that mature eels migrate downstream and spawn in deep water in or near the Coral Sea, and that the adults die after spawning. The larvae ride ocean currents back to the coast, become glass eels and enter Tasmanian estuaries from February to April, then become pigmented elvers and move into the lower reaches of the streams. Every longfin in a river is waiting, sometimes for decades, to make that trip once.

Rules that apply

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Victoria: the Victorian Fisheries Authority lists no minimum size and a combined bag limit of 10 longfin and shortfin eels (as published in October 2026).

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Tasmania: an inland angling licence is needed. The Inland Fisheries Service fact sheet (2024) gives a daily bag of 12, a possession limit of 24 and a minimum length of 300 millimetres. Check the current Inland Fishing Code.

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Queensland: the Queensland Government lists a minimum size of 30 centimetres and a combined possession limit of 10 across all eel species (as published in October 2026).

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New South Wales: NSW DPIRD’s freshwater bag and size limits (checked October 2026) set a 58 cm minimum, a bag of 10 and a possession limit of 10, open all year.

Frequently asked questions

How big do they get?

Most are a metre or a little more and a kilogram or two. Fishes of Australia records landlocked eels, unable to migrate, to 3 metres and 22 kilograms.