My fishing method including fishing river lord boss
Preparation :
1. 3 maneki neko or better luck item
2. 3 temperance (the one that summon gachapon)
3. junk as much as possible (u can go with poisonous mushroom i believe, u will see the reason when u read the method)
4. any bomb except frost bomb (optional)
5. rainy days
6. blessing from fortune wheel or from giving food to ASABA (optional, also increase luck)
Method :
1. go to fishing location with that has large water pool and large land. i prefer go to this bridge in adventurer's path : monument
2. spawn 2 gachapon right on the water
3. Spawn 1 gachapon upper side of the water u gonna fish, make sure there is a space for u to feed the gachapon
4. Equip all luck items. i am using 3 maneki neko
5. feed the gachapon with junk
6. Go away a bit. Things gonna explode. gachapon spawn a lot bombs at the same time.
With high luck and rainy days u can spawn river lord 1-3 times feeding the gachapon. u can go with your own bombs but i prefer save it to destroy rocks in the mine.
Edit : the reason i prefer the place with large land is because i want to get the boss fish, u need to get it away from the river so it cant run to the water