There is only old, good, and super rods in Pokemon Heart Gold.
surf on water or get a fishing rod
You can find them in the Whirl Islands by Surfing or Fishing with a Super Rod.
You can only find it by going house to house in Olivine City.
Use a fishing rod.
Go to the rocky beach area and use the super rod.
you cant get a gold rod but you can get a super rod witch allows you to catch rely powerful water Pokemon. you can find it after you beat the champion, you need to be in Kantoon route 12 then find the fishing guru's house and he will give you your rod.enjoy :)
There is no bad rod, only Good Rod, Old Rod and Super Rod. I can assume you mean the Old Rod in which case you find it in the following places; Red/Blue/Yellow: Vermillion City (Fishing Guru) Gold/Silver/Crystal: Route 32 (Man in Pokemon center) Ruby/Sapphire/Emerald: Dewford Town (Fisherman) Diamond/Pearl/Platinum: Jublife City (Fishing Guru) HeartGold/SoulSilver: Route 32
A Fishing Guru in Olivine City has it.
You can get an Abra at the gamecorner in golden rod and evolve it.
the house nearest to the pokemon center in olivine city
At the Flower Shop in Golden Rod City.
go in the golden rod under ground tunnel