Bait is a general term for one of the many types of quest reward items obtained by completing Professional Fisher Quests.
Use the bait on a Fishing Pole and it will help attract that type of rare fish, crabs and lobsters it's suited for to be caught. Using bait, and fishing in the area the fish is known to live, a player will have 1-3% chance per cast of catching the fish. Without bait, the odds for the rare fish are lower, less than 1%, unless you find a school of magical fish (see: Magical Fish Finder).
To use fishing bait, double-click it and target a Fishing Pole, then use the pole as normal to go fishing.
Only one use of the bait may be active on the fishing pole at a time. While a player can apply the same bait several times to a fishing pole, only one charge will be used and the fishing pole will only have the bait on it for one cast.
When the fishing pole is baited, it will display an additional property of being baited to attract the fish the bait was for.
Anything caught from a baited fishing pole will consume the bait on it, even footwear or sea serpents. If nothing is caught, the fishing pole will remain baited and can be used again.
Bait cups of the same type can be combined by double-clicking one and targeting another. Once done, the original bait up is destroyed and the bait cannot be separated or divided up.
List of Baits
Magical Fish and Crustaceans