Do you man African lungfish?
As the name suggests, breath air when their rivers and ponds dry up during the African dry season, then bury themselves in the dry mud.
Back when I was a kid, you could order them packed in a dried mud packet, put it in water, and they would come out of "hibernation".
Many species grow to about 3ft, one species up to 6ft.
They will eat any fish that fits in their mouth, and in the end require a fairly large tank.
I remember a 3ft one in town that was kept alone in a 130gal 6ft tank, was very personable, but would bite your hand if it got too close.