Lungfish are ancient fish that can be found in Australia, South America and Africa. The group lungfish contains only a few species and no more than a total of six species are known. This six species can be divided into two different families. One family, Lepidosirenidae, contain five species found in South America and Africa. The other family is called Ceratodidae ad contains only one species, the Australian lungfish.
All lungfish share the one common organ that has given them their name. They have developed lungs which allows for them to survive in water with very low oxygen levels where other fish can’t survive. The lungs also allow them to survive out of the water. The lungs found in lungfish are very similar to the lungs found in primitive reptiles.
Lungfish has been present since the Lower Devonian area which means that they have been around for more than 100 million years. The number of species used to be much more numerous in the past but all but six species are now extinct.
Lungfish are easily recognized on how they look. They have primitive looking snakelike bodies. All lungfish species can grow very big and the African lungfish can grow to be more than 2m / 6 feet long.
They are highly predatory species that eats or try to eat everything that fits into their large mouths. (Including aquarium decoration and heaters) Their natural diet consists of fish,crabs, crayfish and anything else they might find.
The Lepidosirenidae family of lungfish can survive in very little water and the African lungfish can survive without water for up to two years. South American lungfish survives low water levels by digging a hole in the bottom mud where they build a nest. They then wait in the nest until the water returns. The African Lungfish is an even better survivor. They don’t settle for building a nest but also cover their bodies with a secretion. This secretion forms a leather like cocoon that helps keep the lungfish moist until the water returns. They hibernate during the time they wait for the water to return and can as earlier mentioned survive in tried out desert like areas for up to two years or perhaps longer.
The Australian lungfish doesn’t hibernate like some other lungfishes. This makes them dependent on water but can be found and survive in very small water bodies.
All Lepidosirenidae lungfish species builds some type of nest in which they deposit their eggs. The male guards the eggs until they hatch. The Australian lungfish doesn’t build any nest. They just deposit the eggs on the bottom within their habitats.