Where at the lake of rage can you get a fishing pole on soul silver?

You can't get a fishing rod at the Lake of Rage in Soul Silver. You need to have the Old Rod first, which you receive in Goldenrod City from the old man near the radio tower.

Here's how you get the Old Rod:

1. Talk to the old man near the Goldenrod Radio Tower: He'll give you the Old Rod after you defeat the Gym Leader, Whitney.

2. Learn how to use the Old Rod: Head to the south side of Goldenrod City and talk to the Fisherman standing next to the pond. He'll teach you how to use the Old Rod.

3. Start Fishing: You can now start fishing in the pond by pressing the "A" button while standing in the water.

Once you have the Old Rod, you can fish in various places, but the Lake of Rage isn't one of them. You'll likely want to head to a different location with the Old Rod to catch some new Pokémon!