Each region has a rod which can be earned and is more effective in that regions fishing spots (Gintel) : r/Genshin_Impact_Leaks

Genshin Impact fishing spots (updated for 4.2) - Polygon

For those that are still hesitating whether to farm those fishes, see the speed difference for yourself. :) : r/Genshin_Impact

All Fishing Spot Locations (DETAILED GUIDE)

Genshin Impact Leaks

Genshin Impact Leaks

Genshin Impact 2.1 leaks: Fishing event, rods, furnishings, and types of fish revealed

Reached the limit for the event fishing spot so I got this bright idea of decimating every other fish until a got a spot full of rusty kois I can catch tomorrow

Genshin Impact 2.1 leaks: New fishing system and fishing rod revealed

Genshin Impact Leaks

New set of Genshin Impact 2.1 leaks reveals Fishing pool, rods, and Fish types