Species · Maccullochella mariensis
Mary River Cod
One of the country's rarest freshwater fish lives in a single Queensland river, and is a legal catch only in a short list of stocked dams far from it.
Family
Percichthyidae
Origin
Endemic
How to tell it
The Mary River cod is the Queensland branch of the cod family, a heavy, golden-to-dark-green fish with a concave head and a mouth that reaches back past its eye. Fishes of Australia, the Museums Victoria reference, calls it one of the country’s most endangered freshwater fishes and lists it as endangered under the Commonwealth’s EPBC Act. It was first described as a subspecies of the Murray cod and is now treated as a species in its own right.
It once lived in the Mary, Brisbane-Stanley, Albert-Logan and Coomera river systems of south-east Queensland. Fishes of Australia says it is now very rare or gone from all but the Mary, and estimated to occupy less than 30 per cent of its historic range there. It reached 40 kg and 120 cm in the past; fish over 5 kg and 70 cm are now uncommon.
Two facts shape the angling. In the wild, and in some stocked dams, it is a no-take fish. And since 1983 it has been stocked into a list of south-east Queensland impoundments outside its home river, where Queensland’s rules allow one fish over a minimum size to be kept. Know which water you are on.
The quick read
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Status: endangered (EPBC Act).
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May it be taken? No take anywhere except listed stocked impoundments, where Queensland allows one fish of at least 60 cm (Queensland Government limits page, checked October 2026).
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Range: naturally the Mary River catchment only. Outside our catalogue, which centres on New South Wales, the ACT, Victoria and Tasmania.
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Size: now mostly under 70 cm and 5 kg.
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Spring closure: no fishing in the Mary River and tributaries upstream of Six Mile Creek, near Gympie, from 1 August to 31 October.
Range in Australia
The wild fish is endemic to the Mary River catchment in south-east Queensland, Fishes of Australia says. None of the waters in our guide sit in that range, and none hold stocked Mary River cod.
The stocked fish are another matter. Fishes of Australia records stocking for recreational angling since 1983 above the walls of Cressbrook, Hinze, Maroon, Moogerah, North Pine, Somerset and Wivenhoe dams and lakes Dyer and Clarendon. Queensland’s current freshwater limits page lists the impoundments where take is allowed, adding Ewan Maddock and Wyaralong dams, Lake Manchester, Lake Kurwongbah, Caboolture River Weir, Enoggera Reservoir and Robina Lakes. Two dams inside the Mary catchment are stocked with the cod but are no-take for it: Lake MacDonald and Baroon Pocket Dam.
Habitat and behaviour
Fishes of Australia describes a fish of every kind of river water in its catchment, from steep, rocky upland streams to big, slow lowland pools. Lowland fish favour deep, shaded water with mud or clay bottoms and woody debris; upland fish favour slow water with undercut banks, rock ledges, boulders and submerged logs and snags.
It eats what a cod eats: other fish, spiny freshwater crayfish, yabbies, shrimp, mussels, frogs and small reptiles, with the big fish living mostly on fish and the juveniles on crustaceans. Fishes of Australia links its decline to the loss of riverbank vegetation and the removal of snags.
Confusing species
Fishes of Australia gives the field marks: golden-yellow to dark green or brown above with dark green to blackish mottling, whitish below; thin white margins on the soft dorsal, anal and tail fins; relatively long pelvic fins; a concave head; a large mouth reaching past the eye; and a deep, short tail wrist.
Against the Murray cod, it says the Mary River fish has a deeper, shorter caudal peduncle and longer pelvic fins, and the Murray cod grows much larger. The Clarence River cod of northern New South Wales is closer still, separated by proportions and fin-spine details.
Fishing for them, and if you catch one
Where a Mary River cod may be kept, in the listed stocked impoundments, you need a Stocked Impoundment Permit if you are 18 or over, as for any line fishing in those dams. Fish them as you would a Murray cod in a timbered lake; our page on fishing timber for Murray cod covers the approach.
Everywhere else, including Lake MacDonald and Baroon Pocket Dam, a Mary River cod goes straight back. Both dams are fished for other stocked natives: the Queensland Government lists Australian bass in both, and golden perch and silver perch in Lake MacDonald. The Queensland Government’s advice is to return no-take species to the water immediately. Keep it wet, unhook it fast, and let it swim off. The Mary River Catchment Coordinating Committee says many wild cod are still caught and released by anglers fishing for other species, and that pulling a male off his nest, even briefly for a photograph, can cost thousands of eggs.
Spawning season
Fishes of Australia says the species spawns in spring once water is warmer than 20 °C. Females lay large adhesive eggs on hard surfaces such as submerged logs, rocks or clay banks; they hatch in about four days, and the male guards the eggs and then the larvae for 7 to 10 days. The Mary River Catchment Coordinating Committee describes the August-to-October breeding period as the time the fish is most vulnerable, with males defending and fanning the eggs, and that is why the river closes in those months.
Rules that apply
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No take: the Queensland Government’s limits page lists the Mary River cod as no take, with an exception for listed stocked impoundments: a minimum size of 60 cm and a limit of one (checked October 2026).
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Lake MacDonald and Baroon Pocket Dam: both are stocked with Mary River cod and both are no-take for it, according to the Queensland Government’s Stocked Impoundment Permit pages.
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Spring closure: the Mary River Catchment Coordinating Committee, quoting Queensland’s fisheries rules, says no person may possess or use a fishing line from 1 August to 31 October in the Mary River and adjoining waters upstream of its junction with Six Mile Creek near Gympie. Baroon Pocket Dam, Borumba Dam and Lake MacDonald remain open as stocked impoundments. It also reports year-round fishing bans on parts of Obi Obi Creek below Baroon Pocket Dam and on Tinana Creek above Teddington Weir.
Rules change. Check the Queensland freshwater fishing rules or the Qld Fishing 2.0 app before you fish.
Frequently asked questions
Can I keep a Mary River cod from Lake MacDonald?
No. Lake MacDonald is stocked with Mary River cod, but the Queensland Government lists it as no-take there. The same goes for Baroon Pocket Dam.
Where can I legally keep one?
Only in the stocked impoundments listed on the Queensland Government’s freshwater limits page, such as Hinze, Somerset and Wivenhoe dams, and then only one fish of at least 60 cm. Check the current list before you go.
Is it just a Murray cod in a different river?
No. It was once classed as a subspecies of Murray cod but is now a separate species, with a deeper tail wrist and longer pelvic fins, and it never grows as large.