Which fish can survive out of water for over three years?

The fish that can survive out of water for over three years is the African lungfish.

African lungfish survive seasonal drought by burrowing into drying mud and secreting a mucus cocoon around themselves. In this dormant state, called aestivation, they can remain without access to open water for several years—commonly described as up to about four years in extreme conditions.

Their survival trick depends on true lungs, which allow them to breathe atmospheric air through a small passage to the surface. Their metabolism drops dramatically, and nitrogenous waste is converted from ammonia into the less-toxic compound urea. The fish lives largely on stored energy while its body is protected from dehydration by the hardened cocoon.

This fact is often confused with ordinary air-breathing fish such as snakeheads, climbing perch, or mudskippers. Those species can tolerate air exposure, but African lungfish are specialists in surviving prolonged drought underground. “African lungfish” refers to four living species in the genus Protopterus, all adapted to seasonal freshwater habitats.