Here's why:
* Rainbow Pokemon don't exist: There's no official "rainbow" Pokemon type or species in the Pokemon games.
* Catching Pokemon in battle arenas is rare: Battle arenas are usually for competitive battles, not catching Pokemon. You typically catch Pokemon in the wild or through special events.
Here's what you can do to catch Pokemon:
* Explore the world: Travel to different locations, like forests, caves, or beaches.
* Use Poke Balls: Throw Poke Balls at wild Pokemon you encounter.
* Weaken Pokemon: Use attacks to lower a Pokemon's health before attempting to catch it.
* Use special items: Items like Berries and Poke Balls can increase your chances of catching a Pokemon.
Enjoy the thrill of the hunt!