Pekiz

Unfortunately, you won’t be able to catch Staryu in the Kanto-generation games (FireRed / LeafGreen) right at the start of the game. The main reason is that this Pokémon can only be caught using the Super Rod, which you receive roughly halfway through the story. Additionally, if you’re playing the official versions, Staryu is exclusive to LeafGreen. It cannot be found in the wild in FireRed, and you can only obtain it through trading (or cheat codes, if you’re playing on an emulator).