Unlike most fishes, the Australian Lungfish has the unique ability to breathe air using a single lung.

The Australian Lungfish is found in still or slow flowing freshwater pools in river systems of south-eastern Queensland. It has a single lung, whereas all other species of lungfishes have paired lungs. During dry periods when streams become stagnant, or when water quality changes, lungfishes are able to surface and breathe air.

Worldwide, there are six species of lungfishes. Four species in the genus Protopterus (Family Protopteridae) are found in Africa. One species Lepidosiren paradoxa (Family Lepidosirenidae) is recorded from South America. The Australian Lungfish is the only species in the Family Ceratodontidae.

The African lungfish Protopterus annectens is known for its ability to bury in the mud. At the start of the dry season when water bodies dry up, this species is able to secrete large quantities of mucous. The mucous hardens to form a cocoon in which the fish stays dormant for several months. Other species of African lungfishes also have this ability to varying extents.

The South American Lungfish can only breathe air. These fish are called obligate air-breathers and will drown if denied access to the surface. It survives for months in a resting chamber of moist mud and mucous.

The Australian Lungfish does not bury in the mud or form a cocoon and cannot survive for more than a few days out of water.

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