Australian Lungfish Care Guide - Habitat, Diet & Breeding

The Australian Lungfish is one of the world's most ancient surviving lineages of bony fish. Its elongated body is covered in large, overlapping scales, while broad, lobed fins give it an almost amphibian-like appearance. Olive-brown to grey colouring helps it blend with the vegetation and shadowed river margins of its native waterways.

Unlike most fish, this species can breathe atmospheric air with a single functional lung connected to the digestive tract. It still relies primarily on its gills, but surfacing to gulp air allows it to tolerate periods when water is warm, slow-moving or relatively low in oxygen. Its ability to breathe air is one of the features that links lungfish to the evolutionary history of land vertebrates.

Australian Lungfish are generally slow-moving and deliberate rather than active open-water swimmers. They spend much of their time near the bottom, investigating the surroundings with their sensitive mouths and lobed fins. Adults are usually solitary, although several may occupy the same broad waterway where suitable habitat is available.

In the wild, they inhabit permanent freshwater rivers, streams, lakes and reservoirs with aquatic vegetation, submerged roots and a soft or silty bottom. They are long-lived animals that may survive for many decades, making them a serious long-term commitment as well as a fascinating example of ancient fish evolution.

This species is protected in Australia and is not an ordinary ornamental aquarium fish. Its enormous eventual size, specialised legal status and demanding space requirements mean that it is primarily maintained by licensed institutions and specialist public or private facilities rather than typical home aquarists.

Australian Lungfish are native to subtropical eastern Australia, particularly the Mary and Burnett river systems in Queensland. They have also been introduced to some other waterways in southeastern Queensland, but their natural distribution is limited and fragmented.

Australian Lungfish require a specialist enclosure rather than a standard aquarium. A full-grown specimen needs at least about 10,000 litres, with considerably more space preferable, and a long footprint of roughly 4 metres or greater is a practical starting point for an adult. The enclosure should provide broad swimming space, strong filtration, excellent oxygenation, secure access to the surface and a substantial water depth, while leaving room for the fish to turn without damaging its fins or body. Use smooth sand or fine rounded gravel, avoid sharp decor, and include sturdy submerged roots or hardy aquatic plants only where they cannot obstruct movement or the animal's access to air. Because this protected species is not appropriate for most home setups, keepers should confirm all licensing and welfare requirements before acquisition.

Up to about 150 cm (59 in) in total length. Females are often slightly larger and heavier than males, although individual size varies considerably with age and habitat.

Australian Lungfish are carnivorous to omnivorous opportunists. Their natural diet includes snails, mussels and other molluscs, insect larvae, crustaceans, worms, frogs and some fish, with plant material also consumed incidentally. Captive specimens can be offered a varied diet of high-quality sinking carnivore pellets alongside appropriately sized earthworms, mussels, prawns and other marine or freshwater invertebrates. Food must be sized carefully because adults can take surprisingly large prey, and uneaten food should be removed promptly.

Australian Lungfish are best kept alone because their size, predatory feeding behaviour and tendency to swallow smaller animals make conventional community stocking unsafe. Very large, peaceful, robust fish that occupy different areas of the enclosure may sometimes be considered by experienced public-aquarium professionals, but even large tankmates can be injured or outcompeted. Small fish, shrimp, crayfish and delicate or highly active species should be avoided, as should fin-nipping fish and territorial cichlids.

Australian Lungfish are exceptionally difficult to breed in captivity and are not suitable for routine home-aquarium breeding projects. In nature, spawning usually occurs during the cooler-season rains, when pairs deposit eggs among aquatic plants in flowing or well-oxygenated water. Successful captive reproduction requires very large specialist ponds, carefully managed seasonal conditions and substantial expertise; collecting or breeding this protected species may also require permits under Australian and local wildlife regulations.

Australian Lungfish show little obvious external sexual dimorphism. Mature females are commonly somewhat larger and more robust, while males may develop a slightly broader or more angular head, but reliable sexing generally requires experience and examination of mature animals.