you can't. to get an espeon or umbreon, you need to evolve an eevee at certain time of day. leafgreen/firered don't have clocks. you have to trade the eevee to ruby/sapphire, max out friendship and level up in the pm for espeon, am for umbreon.
you can by evolving eevee but not by capturing
You can only trade it from the Johto region or the Hoen Region.
Charizard, suicune, flareon, absol, articuno, and espeon.
so far, you cannot evolve eevee either to umbreon or espeon on FireRed because on FireRed and LeafGreen, there is no clock system. You must trade eevee to Emerald for evolving to Espeon or Umbreon
You can't. It evolves by the time of day. Since there isn't a clock, eevee won't evolve into espeon OR umbreon.
You obtain an Eevee, then train it during the day. Do not give it an evolution stone or you will end up with a different Pokemon.
Only after you obtain the National Dex and you trade one over from Ruby/Sapphire/Emerald.
Evee will never evolve to espeon or umbreon in firered because the game doesn't have internal time so to get an espeon or umbreon you must trade your evee to a game with a internal clock like ruby, sapphire and emerald. Also you can trade an espeon obtained from colosseum or even xd gale of darkness.
Yes it is possible to get Espeon and Umbreon in Pokémon FireRed but you cannot physically evolve Eevee into either Espeon or Umbreon in Pokémon FireRed due to there being no time cycle in the game so you will need to evolve Eevee into Umbreon or Espeon in Pokémon Ruby, Sapphire or Emerald and then trade it over to FireRed.
Espeon is the psychic evolved form of Eevee. It is a psychic pokemon.
Espeon cannot evolve.
Its not possible to get espeon in leafgreen or firered because there is no in game clock so trade evee to a game with a in game clock like ruby and sapphire then train it to become espeon. Optional other ways: If you have Pokemon colosseum or Pokemon xd gale of darkness you can trade an espeon from either game (in colosseum you begin with espeon and umbreon trade espeon to leafgreen and in xd gale of darkness in gateon port a sailor in the parts shop will allow you to get items to evolve your evee choose the dawn shard then train evee a few levels to have it become espeon then trade it to leafgreen remember both colosseum and xd gale of darkness and leafgreen must have be beaten and for leafgreen you need the national dex and the ruby and sapphire to receive the espeon from either game).