Fish People In New York (A Dream I Had)

So I'm in a generic, New York type city. In fact, I'm pretty sure it's New York. And then a flood comes slowly - a gigantic wall of water, almost as high as the skyscrapers, advancing on all of us, but so slowly...almost at a walking pace. So I begin to run away from it, for a couple of miles. Slowly I start running uphill, and slowly the roads turn into the familiar ones of my real-life hometown, Swansea (UK). I realise that the flood has stopped, and when I look back the water is almost up to the very top of the New York skyscrapers. So I relax and start walking. I meet a few people - a woman with a baby, a girl of my age and two young boys - and we all have to go to this first-aid room thing, even though none of us are hurt. The waiting-room is crowded, only a few chairs left empty. So we sit down, and this is when I learn of the fish people: beings who came with the flood, with razor sharp teeth and faster than sharks. Someone said that their singing is so beautiful it would be worth leaning your head to the water to listen to it - if not for the fear that they would bite you with their fearsome teeth. If you were bitten by one of them three times, you would soon become one of them. Everyone in the room was scared of the fish people.
Then, two people come up to us, and it is clear that I am the only one to notice them. They have also clearly been bitten by the fish people, since their faces are covered with gashes and blood and they have strange smiles on their faces. One of them bites the boy next to me, and then the boy suddenly starts talking a peculiar foreign language, and a large, glowing lightning bolt-shaped mark suddenly appears on his head. I try to kill the two bitten people with my bare hands, pulling out clumps of their flesh from their faces. But during my endeavours I get bitten three times, and so I know I'm going to turn.
I stagger down to the edge of the water, to a sandy stretch of warm stone. There is a boy there too, about 19 years old. I see shapes moving in the water, and a peculiar light. Then we turn, and fall into the water.
From here on, it is practically heaven. The water is cool, and transfused with a strange golden light that dances off the bubbles. The fish people swim around us, with huge welcoming smiles on their happy faces, recognising newcomers to their own kind. We swim to a house - for some reason we walk around inside, although it is still filled with water it feels quite dry - and are welcomed by one of the leaders, a tall, stately woman who reminds me somewhat of Meryl Streep. She gives us a tour of where we'll be living, and the place seems to have a distinctly Georgian feel. I am extremely delighted by the fact that they have an enormous library, and intrigued because none of the books are falling apart in the water.
We go to a feast, and me and the boy keep asking people how long we live. No one seems to want to answer, until one of them tells us reluctantly that we will live for 160 years. Then the two of us go to this sort of stone platform, covered by an arch, that stands just above the surface of the water. We can just about see the faces of some of the humans on the shore, avoiding the water and scurrying about with worried, pained faces. The boy goes to the edge of the arch and sings in a glorious, booming voice. I sing too, hidden back in the shade, but just as joyfully. I think this is where the dream ends.