Early into Stardew Valley, Willy will give you a fishing pole, which unlocks fishing. Fishing is a big part of Stardew Valley and a great way to make money early on in the game, but there are a few mechanics you won’t be able to use right away. One of those mechanics is bait, which can be used to cause fish to bite faster.
How to use bait
The reason you can’t use bait right away is that the Bamboo Pole Willy gives you doesn’t have the ability to use bait. Instead, you will need to upgrade to the next tier of fishing pole, the Fiberglass Rod, which has a slot for bait. The Fiberglass Rod costs 1,800G and is unavailable until you reach Fishing Level 2, which will require you to do some fishing. Every fishing rod you unlock after this point will have a bait slot. Bait is also used in Crab Pots, which will only catch something if it has a piece of bait in it, and which you have to refill. Holding bait and interacting with the Crab Pot will place it inside.
Once you get a fishing pole that has a bait slot, you can equip bait directly from your inventory.
The fishing rod itself can have the bait added directly to your inventory by moving it to the fishing rod. Fishing rods can hold a large amount of bait, so you don’t have to reload in between fish.