I swear, I don't know how guys get these topics to cause so much debate. Hahaha
Here are the facts about the Red Gyarados of the Lake of Rage.
In the anime, Team Rocket set out for the Lake of Rage, located in northen Johto, to try and force Magikarps to evolve. They suceeded, but by forcing a Magikarp to evolve, it evloved differently, creating the Red Gyarados.
Now, some one you are wondering if I am gonig to change it's shiny color. And the answer is no, I can't really understand why I would actually. I mean, even in the games, it appears red when its shiny. Again, it's color will not change.
Also, there are some similar questions concerning Pokémon with variations. And it is whether Pokémon that have a different color variation will have a different color shiney. And the answer to that is yes, they will. Any Pokémon that has a regional difference that has a different color, will have a different shiny color. So that means, shiny versions of Pokémon that are extremely rare, like the White Bellied Horsea/Seadra/Kingdra, if found shiney, will be wanted dearly.