These are the ones that you can't catch in Fire Red but are in Leaf Green.
-Bellsprout/Weepinbell/Victereeble
-Vulpix/Ninetales
-Sandshrew/Sandslash
-Slowpoke
-Staryu/Starmie
-Magmar/Magby/Magmortar
-Pinsir
Hope this helped!!
In alpabetical order:
Azurill, Azumarill, Bellsprout, Magby, Magmar, Mantine, Marill, Misdreavus,
Ninetales, Octillery, Pinsir, Remoraid, Slowbro, Slowking, Slowpoke, Sneasel,
Starmie, Staryu, Weepinbell, Victreebel, Vulpix
Most pokemon that are from the Kanto region which is where Firered is based around will need to be traded to Emerald for example the starter pokemon, the legendary pokemon, and a couple other in game exclusives like Eevee and Omanyte. There's also a couple Johto pokemon that can be obtained in Firered that cannot be obtained in Emerald like Hoppip.
I know you can get vulpix and magmar in leafgreen only... i think also you can only get either staryu or shellder but not positive
It must be traded to you from emerald or Pokemon colosseum.
Shellgon must be traded from Pokemon Ruby, Sapphire, or Emerald. None of the Pokemon introduced in these games are in FireRed.
Clampearl cannot be caught in Fire Red and must be traded.
Vulpix evolves into Ninetales. This is the only Pokemon caught in Emerald that can evolve from a firestone. If you have traded an Eevee or a Growlithe to your Emerald game, they can evolve too.
Rayquaza can be caught in Ruby, Sapphire and Emerald in the Sky Pillar. However, in Pokemon Emerald it can be caught before defeating the Elite Four. It can also be caught in Pokemon HeartGold/SoulSilver after obtaining the Jade Orb by showing Professor Oak both a Groudon and Kyogre from both HeartGold and SoulSilver (one of the two must be traded).
You get one Johto starter in Emerald for completing the Hoenn Pokedex. You can trade them into FireRed. Unfortunately, Croconaws (along with Totodiles) cannot be caught in Pokemon FireRed. You must have one traded to you from Emerald.
It must be traded to you from emerald or Pokemon colosseum.
You can't. It must be traded from FireRed or LeafGreen.
You can't. It must be traded from FireRed of LeafGreen.
Shellgon must be traded from Pokemon Ruby, Sapphire, or Emerald. None of the Pokemon introduced in these games are in FireRed.
Shroomish is not available to be caught in the wild in Pokemon FireRed, it must be traded from Ruby or Sapphire.
You can't. However, in Pokemon Emerald, a Ditto can be traded in from a FireRed/LeafGreen game. the top is right but in Pokemon emerald you can find a ditto in the dessert underpass
Dialga doesn't even come into play until Pokemon pearl.AnswerDialga cannot be caught in Pokemon Ruby or Sapphire. It can only be caught in Pokemon Diamond or traded to Pokemon Pearl. Pokemon such as Lucario, Palkia, Darkrai are also exclusive to those two versions. The only Pokemon that may be caught in Pokemon Ruby are the Pokemon in the Hoenn Pokedex and Pokemon from Kanto and Johto generations may be traded from FireRed, LeafGreen and Emerald.
The Growlithe cannot be found in Pokemon Emerald but you can trade it fromPokemonFirered.growlithe cannot be caught in emerald, Sapphire or ruby. it must be traded from fire red
Firered and leafgreen can't catch or see any hoenn Pokemon all must be traded to you from ruby, sapphire or emerald.
All 3 must be traded from either ruby, sapphire or emerald.
Clampearl cannot be caught in Fire Red and must be traded.