Neoceratodus forsteri is the most conservative of the living lungfishes, morphologically close to fossils more than 100 million years old. It has a single lung, retains well-developed gills that handle most gas exchange in oxygenated water, and surfaces to gulp air chiefly when the water is warm, stagnant or the fish is exerting itself.
That combination leaves it dependent on permanent water. It cannot form the cocoon that lets Protopterus wait out a dry season, and it lacks the paired lungs and near-obligate air breathing of its African and South American relatives. It spawns among aquatic plants in spring, laying large eggs on submerged vegetation rather than guarding a nest.
The dependence matters for its conservation. Weirs and impoundments on the Burnett and Mary rivers have altered flows and drowned or removed the shallow weedy margins the eggs need, and the species is listed as Endangered. How much recruitment currently occurs in altered reaches remains an open question.