The fishing mechanic is no stranger to video games (think of your days in Pokemon, Legend of Zelda, and Breath of Fire) but it seems that Stardew Valley has managed to bait and fish players on its own challenging and entertaining approach to it. Your fishing journey begins in Pelican Town where you’ll meet an older gentleman by the name of Willy, a fisherman who owns his own Fish shop and generously gifts you your first fishing rod—the Bamboo Pole. The Bamboo Pole is the perfect fishing rod for beginners because it requires absolutely no bait and is great for catching small fish.
How To Catch Fish

The first things you’ll need to do in order to fish
How To Use Bait

Once you’ve gained some experience in fishing with the Bamboo Pole, you’ll begin to level up your fishing skill. Make sure to keep at it until you’ve reached level 2, and you’ll be able to buy a Fiberglass Rod (an Iridium Rod requires at least a level 6 fishing skill). Now you'll be able to use some bait. This time around, you’ll have to buy your own fishing pole.
Once you’ve purchased your new rod, you’ll need to get bait. You can get both of these things at Willy’s Fish Shop. Once you’ve purchased some bait and equipped your new fishing rod, you’ll be able to bait your fishing pole by using the action button. This will attach one piece but if you’d like to attach more than one, then left click on it. Every time you go fishing you’ll use up one piece of bait. Remove the bait by using the action button on your fishing pole in your backpack. Now you've learned how to bait in Stardew Valley.
How To Use Tackle

Once you’ve leveled up your fishing skill enough and purchased an Iridium Rod, you’ll be able to use tackle. Many players might use this in lieu of bait since all bait really does is speed up the fish biting process. Different types of tackle have various effects on the fishing experience and much like bait, you can buy or craft it. Tackle is attached same way bait is. The only difference with tackle is that it can be used more than once but it will lose its durability over time.