Symbolism, Imagery, Allegory
Ezekiel predicts that the Dead Sea, which is still salt-water today, will eventually become fresh-water and have fish in it, thanks to a healing stream of water that will pour out from under the Temple:
He said to me, This water flows toward the eastern region and goes down into the Arabah; and when it enters the sea, the sea of stagnant waters, the water will become fresh. Wherever the river goes, every living creature that swarms will live, and there will be very many fish, once these waters reach there. It will become fresh; and everything will live where the river goes. People will stand fishing beside the sea from En-gedi to En-eglaim; it will be a place for the spreading of nets; its fish will be of a great many kinds, like the fish of the Great Sea. (47:8-10)
If we take this literally, it means just what it says. But it might mean that the presence of God in the Temple will bring a society and a people who once seemed corrupt and dead back to life. The "waters of life," like the "streams in the desert" the Book of Isaiah or the holy water used during baptism, symbolize purification: a fresh start. They can cleanse and renew a people spiritually. Not to mention revive the sushi industry in Israel, which totally tanked after the Babylonian invasion.