look in your pokedex at the area.
You can't get a Tentacruel by just fishing/surfing in Pokemon FireRed. You have to Evolve a Tentacool (It evolves at level 35).
You can find Pidey in a Pokemon Outbreak in Pokemon Diamond
where do i find a totodile in Pokemon diamond/pearl on nintendods
You can not find or get manaphy on Pokemon diamond but you can by hacking, trading or... if you have Pokemon ranger you have to complete the manaphy mission and then you can put it onto diamond.
You can't find a Ho-ho in Pokemon Diamond. You have to migrate.
To get a Manaphy in Pokemon Diamond you have to get Pokemon ranger and defeat it and you have to trade it to Pokemon Diamond,Platinum or Pearl.
its not a Pokemon
Not really that rare... in Pokemon Diamond you can find Sunkerns on Route 204
you have to catch all of the pokemon in diamond or SEE all of the pokemon
you can find legendary Pokemon by using your Pokemon tracker
there isn't a Pokemon ranch on Pokemon diamond, its a complete other game! there isn't a Pokemon ranch on Pokemon diamond, its a complete other game!