After you have defeated the elite 4 the game will restart and you will appear in your bedroom. Then your mother will tell you your rival wants to meet you in the fight area. Fly to snowpoint city then go STRAIGHT down from the gym. You will see a sailor with a boat. Talk to him and he will ask to take you to the fight area
in the fight area
A fisherman at the fight area gives it to you.
You can receive a Super Rod from a fisherman in the Fight Area on Pokemon Platinum, Diamond and Pearl.
you catch banette at the fight area, resort area or survival area
In the fight area you can access the Battle Frontier, and route 225 to Survival area, or route 230 to Resort area.
You can get it from a fisherman at the fight area.
you have to have beat Pokemon league and get the national pokedex then go to the snowpoint city and sail to fight area. go east of the fight area and go strait on.
Catch all the pokemon in the region. Get the national pokedex
I think you are mixing up the battle area with the battle frontier at fight area. That's my answer
it can be found in a lot of places in platinum. just use the super rod you got from the fisherman in the fight area.
fight team Gaelic and then there gone
Find a fisherman in the Fight Area It is at northwest area (top left)