Life isn't all nice, and death isn't all bad.
A fish in the water, has never seen life because it's never imagined death.
A fish out of water is the closest to living because it's in a struggle against death, and it knows it'll die eventually.
It's about taking life as a struggle, which it is, instead of a mundane everyday routine and valuing it. And remembering that it'll all end one day, cuz that's what gives life value.