From V Rising Wiki
Fishing is a non-combat activity that permits the player to get fish, reagents, and recipes.
Catch a Fish
Players need to craft a fishing rod on a woodworking bench, get a fishing rod, go to the body of water and look for a specific hotspot. They are white bubbling areas where the audio signal is weak. Equipped with a fishing rod and cast when facing a hotspot by pressing the attack button. Wait for the big splash to appear and immediately use the attack button to catch up with it. Delays lead to failure. Hotspots are limited to casts and disappear when you catch up, regardless of whether the cast was successful or not.
Rewards
Certain zones have loot dedicated to fishing, in addition to the general loot that allows you to fish at different rarities in each zone. As a general rule of thumb, you can catch the same "tier" recipe as the zone. Farbane Woods fishing spots provide recipes for learning at the study table, fishing on Dunley Land provides recipes for research, and fishing at Silverlight Hills provides recipes for Athena Eum.
| The Fish |Cursed Forest (1%) |Very Rare |}
Note: Rarity and location is based on early access data, and a small sample size.