South American lungfish
Air-breathing fish from South American swamps
The South American lungfish is the sole species in its family, living in Amazon and Paraná basins. It breathes air, burrows in mud during droughts, and possesses one of the largest known genomes.
- Reaches lengths of up to 125 cm
- Survives droughts by burrowing in mud
- Males provide oxygen to eggs via fins
- Has a genome 30 times larger than humans
- Adults breathe air due to reduced gills
What it is
This fish has an elongated, eel-like body that can reach 125 cm. Adults are brown or gray, while juveniles display gold spots on black. Its pectoral fins are thin threads, and pelvic fins sit far back. Unlike most fish, its fins connect to the shoulder with a single bone, resembling land vertebrates. Gills shrink in adults, making them rely on air.
Where it lives
It inhabits swamps and slow waters in the Amazon, Paraguay, and lower Paraná River basins. These habitats in South America often dry up seasonally. The fish survives these changes by burrowing into mud when water disappears, waiting for rains to return.
How it lives
Juveniles eat insect larvae and snails. Adults add algae and shrimp to their diet, crushing food with mineralized tooth-plates. During dry seasons, they burrow 30 to 50 cm deep into mud. They seal themselves in mucus and slow their metabolism to survive droughts until water returns.
Breeding and life cycle
Mating begins with the rainy season. Parents build nests for young that resemble tadpoles with external gills. Males develop vascular structures on pelvic fins to release oxygen into the nest water. Young start breathing air at about seven weeks old.
Fish and people
Indigenous Tupi speakers call it piramboia, meaning snake-fish. Other local names include pirarucu-bóia and caramuru. Scientists study it for its unique biology, including its massive genome and ability to survive extreme environmental changes.
Status and threats
Fossils show this species existed during the late Cretaceous period. Recent studies reveal it has one of the longest genomes known, with 91 billion bases. Low levels of specific RNA may contribute to this genetic size.
Questions people ask about South American lungfish
How does the South American lungfish survive dry seasons?
It burrows into mud up to 50 cm deep and creates a chamber. The fish secretes mucus to retain moisture and significantly slows its metabolism until the rainy season returns.
Why is it called a lungfish if it lives in water?
Adult gills are non-functional, so it must breathe air. It has evolved pulmonary mechanoreceptors to handle both droughts and floods, making air breathing essential for survival.
What do South American lungfish eat?
Juveniles feed on insect larvae and snails. Adults are omnivorous, consuming algae and shrimp as well, which they crush using heavily mineralized tooth-plates in their jaws.
Good reading and sources
- South American lungfish on WikipediaEncyclopedia
- More photos on Wikimedia CommonsPhotos
- Wikidata recordOpen data
The facts on this page come from the Wikipedia article "South American lungfish", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.
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