you cant get the gym leaders Pokemon unless you go to a certain cave and find one of the two... your welcome :)
The 7th leader is Blaine. He uses fire pokemon.
The gym leader of Mahogany Town. He uses Ice-type Pokemon. You face him as the 7th gym leader in the game.
The 7th gym leader in Pokemon yellow is in Cinnebar Island, which is south of Pallet Town. You need a Pokemon with Surf to get there.
The 7th gym leader is Blaine. He the gym leader of Cinnabar Island gym. He uses Fire type Pokemon and he will give you the TM that contains Fire Blast when you defeat him.
His Pokemon are: Vanillish,Cryogonal,And Beartic.
snowpoint city
Candice
the best way to beat the 7th gym leader is with a fire type Pokemon
She has medichan,snover abisnow,and sneasle
Tate and Liza have: Solrock and Lunatone
Cinnabar Island
break the snoballs with enuff speed