Below lavender town there is a big pathway on the water. There is a house that is just a little bit below you can find Snorlax and the fisherman will give you a super rod, and then in Fuschia city in the house next to the safari zone warden's house. There is another fisherman that will give you a good rod.
And finally you can find the old rod in the house next to the pokemon center in Vermillion city.
Hope this helped bud :D