True but whats the easiest way to get a level 55 Gyarados?
Catch one with a Super Rod right outside of Victory Road.
Well, I beat it, but to get the Super Rod, you would have to beat the Elite 4 anyways, to get the super rod because its on the Battle Isles.
True but whats the easiest way to get a level 55 Gyarados?
Gyarados learns Dragon Dance at level 44.
You can capture a lowish level one with the Good Rod then level it up to 44.
Either way, congrats.