get an everstone.
You get pupitar by evolving larvitar.
L.v 22
You'll need to trade for it, because evolving Feebas will be impossible in Pokemon HeartGold and SoulSilver.
To Stop Evolution:Tap the B Button Repeatedly until Evolution stops (While Evolving)Make your Pokemon hold an Everstone (Does not Evolve while Hold)Note: Trading Pokemon that Evolve can not be stopped.
Azumarill doesn't evolve according to level in Pokémon HeartGold because it's not capable of evolving at all.
To keep your Pichu from evolving, give it an Everstone. It will not evolve until you take the Everstone off of it.
If you keep it from evolving it can (depending on the pokemon) learn more moves that it wouldn't learn if it evolved. So to answer your question people who want those moves.
You can only obtain hitmonlee by evolving tyrogue. Tyrogue is obtained in Mt. Mortar. Source: Bulbapedia
get a haunter by evolving gastly then trade to a friend and trade back and you have a gengar hope this info helps :-)
Keep walking with them, and your friendship with them will increase.
you keep on battling the gyms
check your map and keep looking