I think you may be talking about Nat's lucky fishing rod, fishing with +25. If you have completed 225 to 300 fishing tasks before, you can go directly to the drowning swamp 59.60 and ask Nat for it. If it's not finished, go to the npc next to Augeri Ma's fishing trainer to pick up the task, and let Nate catch four fish. It is recommended to use bright pearl bait, which is easy to catch.