Question

which fish can remain out of water for longest duration

Answer 1

HELLO DEAR,

$\large{\underline{Lungfish (Dipnoi):}}$
Six species , have limb like fins, and can breathe air. Some are obligate air breathers, meaning they will drown if not given access to breathe air. Some species will bury in the mud when the body of water they live in dries up, surviving up to two years until water returns.


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Answer 2

Answer is Snake heads or Dipnoi. 

The Fishes are belongs to Class PISCES of Chordates. Fishes cant survives without the water. Although there are some kind of the Fishes which can survives without the water for longer duration because they have the special structures in our body which is scientifically called as lungs. Thus, all those ships which can survive without the water for some duration is called as LUNGS FISH.

Examples of the Fish which can survives without the water for longer duration are 

1) Snake heads → This Fish have the highest ability to survives outside the water for the longer time. 
2) Dipnoi → This Fish too have the ability to survive outside the water. 



Hope it helps.