>>545539284
1. Makes the thing you keep the fish in for the minigame bigger
2. Makes fish you catch bigger so they sell for more coins. Grandmaster rod consistently catches max-size fish
3. I haven't tested the lower rods but
Lv 7 Advanced Rod lets you use the geniemon trait to automatically reel in any fish up to purple rarity in icelake.
You can auto-reel one of the purple fish in Purgatorio and neither of the purple fish in the sewers
Lv 12 rod allows you to auto-fish any purple fish with the geniemon trait
Lv 20 allows you to auto-fish the gold fish in all 3 fishing holes

>>545260965
I already have that. Its ability to auto-fish is tied to your rod rarity. I havent bothered testing the lower level ones but Lv 7 can auto-fish any fish up to level 4 (1 purple fish on purgatorio is excluded, both purple fish in sewers are)
Lv 12 lets you auto-fish all purple fish
Lv 20 lets you auto-fish the gold fish