Get a Wailmer and evolve it. It evolves into Wailord at level 45.
The only way to obtain a Wailord is to trade it from Ruby, Sapphire, and Emerald.
You can't catch it in Pokemon Sapphire, Ruby, Emerald. The only way to obtain it is to buy it in the Game Corner for 9999 slot coins in Pokemon FireRed and LeafGreen and then trade it to your Ruby/Sapphire/Emerald game.
You will need to migrate from Pokemon Ruby/Sapphire/Emerald.
The only way to obtain Shuckle in Ruby or Sapphire is to trade it from Emerald, Colosseum, or XD.
you can't get it in Pokemon ruby, you have to trade with a friend that has Pokemon sapphire or emerald.
You must trade kyogre from sapphire or emerald to firered to obtain it.
Meditite is a Psychic and Fighting type Pokemon that is not available for capture in Pokemon Emerald. It is however in Pokemon Ruby and Sapphire, so it may easily be traded to Emerald from another game.
It isn't possible to obtain a wild one in Emerald. You have to trade with someone (or youself) with a Ruby or Sapphire
The water type Pokemon Poliwhirl is number 061. In the Pokemon Ruby, Sapphire, and Emerald games for Nintendo Gameboy, the only way to obtain a Poliwhirl is by trade.
There is no cheat to obtain Kyogre in Pokemon Ruby. To obtain Kyogre and Pokemon Ruby, one must trade with a trainer that has obtained Kyogre in Pokemon Sapphire or Emerald.
It is possible to obtain a Custap berry in Pokemon Pearl. To get it you have to trade from Ruby, Sapphire or Emerald version.
Only after you obtain the National Dex and you trade one over from Ruby/Sapphire/Emerald.