No, you need to trade for it.
Pokewalker, quiet cave.
To catch Feebas on Pokemon Soul Silver is on a pokewalker route.The route I think its Blue Lake.
Chat with our AI personalities
The Pokewalker.
You can't, the only way is to transfer it from a Pokewalker. To do that, you have to have unlocked Quiet Cave, and Feebas will be one of the wild Pokemon that appear when you use the PokeRadar. Catch it, then transfer it to your SoulSilver.
You'll need to trade for it, because evolving Feebas will be impossible in Pokemon HeartGold and SoulSilver.
No, you can not catch Phanpy in SoulSilver. It is a version exclusive to HeartGold.
Feebas is in the area south from fortree city you must use a rod to catch it.