Go near some water and select the fishing rod out of your bag. You could press select so that you register it, and that you dont need to keep going back to your bag.
Rainy places
Yes, Mudkip is a fictional fish in the Pokemon games. Mudkip is known as "Mud Fish", and first appeared in the game 'Pokemon Ruby and Sapphire'.
Just about anywhere you can fish or surf.
Pokemon Ruby has Pokemon that Pokemon Sapphire does not and Pokemon Sapphire has Pokemon that Pokemon Ruby does not.
You can trade from Pokemon Ruby to another Pokemon Ruby using a link cable.
In the waters of Lilycove. (You have to fish. No surfing.)
You have to fish at Sootopolis City.
Rainy places
U fish on route 118 and 119
Yes, Mudkip is a fictional fish in the Pokemon games. Mudkip is known as "Mud Fish", and first appeared in the game 'Pokemon Ruby and Sapphire'.
Just about anywhere you can fish or surf.
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.
No, there's different Pokemon at different places using different rods.
Fish with good rod in lilycove city.
In order to get a staryu on Pokemon ruby version you have to fish using a super rod on the coast of lillycove. just keep fishing and you will find one.
right before you get to the Pokemon league on safire, ruby, or emerald you surf or fish and you will get one
Groudon is rare and you get him just by following the story line. The only other "rare" Pokemon I'm aware of in Ruby would be Relicanth, a rock/water type fish Pokemon that can be found underwater.