Charlie dove back under and swam downstream, having to go deep to avoid getting hit by the fish heading for their spawning grounds. They still had a long way to go, and many would not make it, either snagged by hungry predators like the bears his troop leader was worried about, or exhausting themselves before they could reach the place they were hatched. He'd read about this in school. Even those that survived the trip lived only long enough to mate once, and then they died of rapid old age.
Bad for the fish, but he felt a thrill as he rose back up and joined in the rush of flashing bodies. Charlie was amazingly fast for a human, but even he could not keep up with the salmon, and he finally surfaced and watched the fish zip around him. Brad was still in the shallows, not wanting to get in over his head. Oh, well. Charlie could enjoy himself. He turned and went back downstream even further before joining the swarm of scaled bodies for another exhilarating high-speed run.
It was strange to think that these salmon were blindly following some instinct that would end up killing them. It didn't seem fair that they would swim hundreds of miles inland, just to die after laying and fertilizing one set of eggs. They lived, what? Two or three years? These were all mature fish, nearing the end of their lives. On the other hand, he'd never have been able to swim among them under any other circumstances. The single-minded drive to spawn overrode the fear that would have made the salmon swerve away from him, and they slid over and around him as if he were part of their number.
He surfaced again, and saw that he had gone past Brad. His friend was peering over the water, and Charlie had to shout to get his attention. "Over here!"
Brad saw him and waved. "How long are you gonna stay out there?"
"All night! This is great! You should try it!" Charlie knew it was hopeless, but gave it his best sales pitch. "It's fantastic! The salmon swim all around you - it's like being one of them!"
"Yeah, well I don't want to be a fucking fish! I'll take my salmon broiled, with butter!" Brad shook his head. "Don't stay out there too long. We gotta be back at camp before lights out."
"Yeah, yeah." Charlie sighed. "One more good run. I'll go further downstream before I start." He turned and let the current push him along, then started to swim lazily through the warm water. Face down, he did not see the pulsing greenish glow that floated through the air just behind him.
Una giggled as she watched the human moving through the water. He was making this so easy! Fae magic was limited in many ways, and could not be forced on victim. Any transformations had to follow some desire or longing, which meant fairies usually had to resort to elaborate tricks or plots to manipulate their victims. This boy had not only opened the door to a delightfully cruel spell, but would also fully understand his fate. She began the changes slowly as the human continued downstream. His skin began to take on a curious sheen, moonlight reflecting off a pattern that became more pronounced. What little body hair he had washed away, and the ample bulge under his speedo dwindled away.
Charlie felt fantastic, moving more easily than he could ever remember. Salmon flashed by him, and he had to resist the urge to turn and start back. This was his last run, and he wanted to make it count. His legs were moving with amazing smoothness, feet propelling him as if he were wearing flippers.
The fairy grinned as the human increased his speed, unaware of the many changes that made him a better swimmer. His skin was covered in silver scales, his feet had lengthened and widened into broad fins that would soon merge to form a tail, and his head was totally hairless and beginning to become streamlined. She did not know if she wanted him to discover his transformation now, or find out what was happening after he had rejoined the salmon run.