There once was a man who married goldfish.
He'd ended up with a couple of the creatures by chance, and found them useless, uninteresting. But on lonely days he watched them, swimming in the tiny tank they thought was the world. Slowly, his heart changed.
Perhaps the goldfish love him, what they know of him, his finger near the glass, cleaning the tank, sprinkling food. Perhaps they think him a fish, want from him what love fishes know.
In solemn and sacred vows beyond their understanding, he marries them, each one. They pass their brief lives with him, never knowing.