Old Rod - This can be obtained from the fisherman near the Dewford Town gym. This will let you catch Pokémon up to level 15 (mostly Magikarp). Good Rod - This can be obtained from the fisherman on the right side of the river on Route 118. This will let you catch Pokémon up to level 30. Super Rod - This can be obtained from the fisherman living in the house on the northern cliff in Mossdeep City. This will let you catch any swimming Pokémon.
The chance of finding a certain Pokémon is based on the area, not on your fishing spot. There is no one spot that will be better for catching a specific Pokémon than another. The only exception to this is Feebas, who can only be caught on certain tiles in a specific area.
If you don’t press “A” soon enough, the Pokémon will get away.
