There are three types of fishing rods in Pokemon Ruby. The Good Rod is found by talking to a fisherman on Route 118.
You are in a route someone says a good rod is good so take it!
:o i just got a super rod.......forgot where i got good rod
lots of things
A fisherman east of mauville city will give you the good rod.
I think you can use a good rod not sure about the old rod super rod is the best
Use it at any body of water you can hook many Pokemon with it.
Using the Old Rod in Pokemon Ruby (or any Pokemon game for that matter) will get you a Magikarp as that is the only Pokemon an Old Rod can catch.
Fish with good rod in lilycove city.
your starter pokemon can be a water type and you can trade water type pokemon with your friends in pokemon ruby
super rod
In Pokemon Ruby you can catch Wailmer on almost every Route that has lots of water. You will need the Good Rod or the Super Rod to fish one up. The Good Rod can be received from a fisherman on Route 118. The Super Rod is given to you by a fisherman in Mossdeep City.
You can catch Magikarp in any body of water in Pokemon ruby. It is very common and you only need to fish with an old or good rod.