South American Lungfish

South American Lungfish Lepidosiren paradoxa

Type of Animal:

Tropical/subtropical stagnant/slow-moving waters-swamps, swampland, low oxygen creeks, low oxygen rivers, river basins, low oxygen tributaries, lakes, weeded river margins, shallow abundantly vegetated waters

S Colombia, S Venezuela, S Guiana Shield, Brazil, E Ecuador, E Peru, Bolivia, Paraguay, N/NE Argentina

Adults brown to gray to blackish in color, juveniles/subadults black w/ gold spots, elongated eel-like body, thin thread-like pectoral fins, far back larger pelvic fins, greatly reduced gills, juveniles have external threadlike gills

Insects, insect larvae, fish, snails, crayfish, shrimp, prawns, clams, amphibians, algae, weeds, stems, carrion, bloodworms

Status in Wild:


Additional Info:

Young: Fry
Group: Solitary
6-7 lbs

3 weeks 

Life Span:
20 years

Body Length:
Adult: 4.10 ft
Young: 0.4 ft

Main predators are crocodilians.
During breeding season, adults construct tunnel type holes in mud lined w/ vegetation, then retreating into tunnel & sealing it off. Both sexes gather to make nest. Once nest made, male kicks female out & guards nest/eggs/newly hatched fry. Breeding most occurs in wettest months of year.
When fry hatch, they look like tadpoles & have 4 external threadlike gills.
To enrich oxygen in nest, males develop highly vascularized distinctive filaments on pelvic fins releasing additional oxygen into water.
Young become air-breathing at 7 weeks old, losing external gills.
Also called Scaly Salamanderfish, American mudfish, Amazonian Lungfish, & Piramboia (Tupi for “snake-fish”) among others.
Prey captured by suction feeding.
Use tooth plates, enlarged cranial rib, & depressor mandibulae to manipulate/chew food before swallowing.
Maturity most likely reached by a year old.

Fun Fact(s):
These fish are obligate air-breathers as adults, needing access to the surface. Though they spend lots of time at the bottom, they’ll drown if not given access to surface.
Fins of these fish attached to body using joints enabling them to move fins like land animals move limbs.
During dry periods/droughts, these fish burrow into mud, making chamber 1-1.67 ft down, leaving few surface holes for air. During this period, mucus layer produced sealing in moisture & metabolism slows down considerably. This state can last for months, even years.
These fish most likely evolved from 4-footed land animals.

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