it is a switch which lets you change the nature and the Pokemon to catch each theme has diffrent Pokemon
in the safari zone
Safari Zone
Dusclops can be found in the Safari Zone in Pokemon Soulsilver. The rarity varies.
Corphish is located in the Safari zone in Pokemon soulsilver, but you need a good rod and it depends on how you arranged your Safari Zone. The Pokemon is most likely located in the Rocky beach and Wetlands in the Safari Zone.
safari zone
In Pokemon HeartGold and SoulSilver, the safari zone is in Johto, past Cianwood City, past Routes 46 and 47.
Safari Zone (special items)
No you can't find Pikachu in the Safari Zone.
Sinnoh Sound on the radio or Safari Zone
You have to trade to get Riolou. No you can find it in the Safari Zone!
Safari Zone after unlocking the usage of the blocks.
Lunatone can be caught wild in the Safari Zone.