route 209
left of pastoria city
At route 209 from a fisherman.
I forgot where I got my great rod but if you go to youtube and put the same question it will show you a walkthrough.
you cant freakin get one
On Pokemon Platinum, Carvanha can be caught in the Great Marsh.PLEASE NOTE: REQUIRES SUPER ROD.
super rod
In Pokemon Platinum the Good Rod is to the right of Hearthome City. The fisherman on Route 209 will give you the good rod.
There is none there only old rod good rod and a super rod
If you can't find a trainer in platinum with a barboach, you can fish in Eterna City with the good rod and try to find one, because i know you can find barboach there.
Old Rod.
a good rod or super rod
I think it is left of Pastoria City. A fisherman has it. Talk to him and he will ask you if you like great rods. Say yes and he will give you one.