Here's why:
* Espeon is a Generation II Pokémon: Espeon was introduced in Pokémon Gold and Silver. Fire Red is a remake of the original Red and Blue games, which do not feature Espeon.
* No Evolution Method: Espeon evolves from Eevee. While you can catch Eevee in Fire Red, it doesn't evolve into Espeon in this game. The evolution method for Espeon (high friendship during the day) was introduced in Generation II.
To get Espeon, you would need to:
* Trade with someone who has it: This is the only way to get Espeon in Fire Red.
* Play Pokemon Gold, Silver, or Crystal: These games allow you to evolve Eevee into Espeon.
Let me know if you have any other Pokemon questions!