How to Become a Pro Angler
Getting your wand
Make your way out of the first area to the blue portal, then take a high-level portal into the area that looks like this.
Weapon altar spins are not guaranteed, so you may have to try a few times. The fishing rod will be on one of the weapon altars in this area. Bring medicine, a compressor, or a grappling hook.
Then, after saving the wand, take it back to the blue area you originally went to get here. (You can also fish in the final boss room if you really want to.)
This icon at the bottom left represents your fishing meter. On the left is tension, on the right is how close you are to catching the fish. To start, right-click, then wait. (I find that waiting 15 seconds for enemies to take a bite is plenty of time, since I’m not sure there’s any visual indication that you’re on the line.)
As a fish, try to keep your stress low by right clicking spamming and dodging enemies. If you pull too fast, the line will break and you’ll have to try again. Keep in mind, there are no breaks! You have to fish and fight at the same time.
Once you get the fish meter to full green, it will show up! Just run into it to grab it. This will unlock an achievement, as you will get 5 hp (regardless of whether your health is maxed out) and 5 gibbons.