Facts About Lungfish

FFacts On Tap Editorial Team Fact-checked Updated April 16, 2026 4 min read

Lungfish are a small but remarkable group of freshwater fish that look like a living bridge between water and land. With both gills and functioning lungs, they can gulp air at the surface and survive conditions that would kill most other fish.

Found today only in Africa, South America, and Australia, lungfish carry an evolutionary lineage stretching back over 400 million years, making them one of the closest living relatives to the ancient fish that first crawled onto land.

Lungfish belong to the subclass Dipnoi, and only six species survive today, found in Africa (four species), South America (one species), and Australia (one species).
Unlike most fish, lungfish have both gills and at least one functional lung, letting them gulp air at the surface when water is low in oxygen.
During droughts, African and South American lungfish can burrow into mud and secrete a mucous cocoon around themselves, entering a dormant state called estivation that can last for months or, in extreme cases, over a year.
Lungfish are exceptionally long-lived. Granddad, an Australian lungfish that lived at Chicago's Shedd Aquarium from 1933 until 2017, was later confirmed by scientists to have been roughly 109 years old, making him the oldest fish ever recorded in an aquarium.
The oldest known lungfish fossils date back roughly 419 million years to the Early Devonian period, and lungfish were once far more diverse, with close to 100 species known from that era.
Lungfish are largely carnivorous to omnivorous, eating invertebrates, mollusks, small fish, and plant material depending on the species and what is available.
Some lungfish species, such as certain African lungfish, build nests for their eggs that the male guards until they hatch, a form of parental care that is unusual among fish.
Lungfish cannot walk on land, but African and South American species use their slender, muscular fins to push and wriggle short distances across mud between pools when water bodies dry up.
Because lungfish are sensitive to changes in water quality and oxygen levels, biologists use them as indicator species to gauge the health of freshwater ecosystems.
In parts of Africa, lungfish are an important food source and are sometimes dug out of their dried mud cocoons during dry seasons for local consumption.
The Australian lungfish (Neoceratodus forsteri) is the only living species that cannot fully estivate out of water and instead relies on breathing air at the surface of its native rivers in Queensland.
The Australian lungfish is listed as Endangered by the IUCN and Vulnerable under Australian federal law, due to its naturally restricted range and threats from dams and habitat loss.
Lungfish young hatch with external gills, similar to amphibian larvae, before developing the gill and lung structures they use as adults.

Frequently asked questions

What exactly is lungfish estivation?

Estivation is a dormant survival state in which African and South American lungfish burrow into mud, secrete a protective mucous cocoon, and drastically slow their metabolism. It allows them to survive months, and in some cases more than a year, without free-standing water.

How do lungfish breathe air?

Lungfish have one or two functional lungs in addition to gills, letting them rise to the surface and gulp air directly. This lets them survive in stagnant, oxygen-poor water that would suffocate most other fish.

Are all lungfish species able to estivate?

No. African and South American lungfish estivate in dried mud, but the Australian lungfish does not form a cocoon; it survives by breathing air at the surface of its home rivers instead.

What is the conservation status of lungfish?

Status varies by species. The Australian lungfish is listed as Endangered by the IUCN and Vulnerable under Australian law because of its restricted range and habitat pressure from dams, while African and South American lungfish are generally more widespread and not considered at high risk.

Can lungfish be kept as pets?

Some lungfish species are sold in the aquarium trade, but they need very large tanks, specialized care, and can live for decades, so they are a major long-term commitment rather than a casual pet.

How do lungfish contribute to their ecosystems?

Lungfish help control populations of invertebrates, small fish, and algae, while also serving as prey for larger predators. Their burrowing during dry periods also helps aerate and mix freshwater sediment.

Sources & further reading

Reviewed by the Facts On Tap Editorial Team

We write every article to be genuinely fun — and genuinely true. Each fact is checked against reputable sources before it goes live. Spotted something off? Tell us and read our fact-check policy.

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