To capture any Hoenn or Sinnoh Pokémon in the game, you have to tune into the Pokémon March Station on your PokéGear either on Wednesday or Thursday. On Wednesdays you'll have the "Hoenn Sounds" while on Thursdays you'll have the "Sinnoh Sounds." In your case, you can capture Minun on a Wednesday while listening to the "Hoenn Sounds." For more information on this you can visit Hoenn & Sinnoh Pokémon. To find the many locations of Minun in the game, you can also visit its location(s) here, Minun - HG/SS.I'm looking for a Minun, but can't seem to find one. There's no PokeRadar in this game, so I know that's not the problem. Either the national dex Pokemon are just really hard to find, or I'm having bad luck. I don't know. Did I forget to do something? I've already beaten all the gyms, and the only thing left to do is beat Red. So...I don't think I forgot to do anything. :|