Fishing

Fishing is accomplished by using a Fishing Pole at a body of liquid while having a Bait item in your inventory. By standing on dry blocks and clicking a point over water, a line is cast into the water. Re-click when the bobber moves in order to reel in the line, and hopefully, a caught item.

Requirements
75 connected tiles of liquid are required (1,000 for oceans, 50 for honey). The width of the top row of continuous liquid tiles (the row where the fishing bobber sits) determines the calculated pond width, and then the depth directly below those is counted. If the pond becomes wider at lower depths, that additional width is not counted. The player may successfully fish in a 1 tile-wide pond, as long as it's 75 tiles deep. The distance of the bobber to the shoreline does not matter.

It is not possible to fish when the player is submerged in liquid, even partially, and even within a completely disconnected body of water. Fishing can however be done while moving, flying, while grappled to blocks, or while standing on top of water, eg. using Water Walking Boots. Fishing can be done in Lava, but requires the Hotline Fishing Hook (not even the Golden Fishing Rod will work in lava).

Quest fishing
Catching a quest fish for the Angler NPC requires fishing in the proper biome and height for the day's current quest, which can be determined by talking to the Angler. You don't need to speak with him beforehand, nor have even encountered him, but the chances of finding the correct area to fish for a quest are much lower without speaking to him first. Quest fish cannot be caught if the player already has that particular quest fish in their inventory, nor if the quest fish was already turned in that day. However, if you put the Quest fish in your safe/bank then you may catch another Quest Fish. You can then transfer the Quest Fish to a chest if you wish. The Angler gives out special rewards when a proper quest fish is turned in.

Factors
Given the prerequisites for fishing are fulfilled, a number of factors influence the quality/rarity of the caught item. All are combined into a total "Fishing Skill" that determines the chances of higher-quality catches. Percentages in the tables below that influence Fishing Skill are marked or.


 * The Fishing Power of the Fishing Pole used.
 * The Bait Power of the Bait used.
 * Equipped items and Potions.
 * The time the player is fishing.
 * The size of the lake. Lakes with fewer than 300 tiles incur a Fishing Power penalty.
 * When fishing without the High Test Fishing Line, there is always a 1 in 7 chance that the fishing line will break on reel-in, forfeiting the caught item. Chances of consuming bait remain the same even if the line breaks. With the High Test Fishing Line equipped, the line never breaks.

Trout.png Fish
These items can be caught at any time. Most can serve as crafting material for Food and other Potions. Some can also craft other item types. Jellyfish can be used as bait. Most can be sold to NPCs.

Slimefish.png Quest fish
These are fish items that can be caught only when their particular quest is active, and serve no purpose other than acquiring quest rewards. Their catch chance is around 1:10. You can determine the day's quest by speaking to the Angler NPC.

Scaly Truffle.png Usable Items
These items can be used directly without further crafting. Some are Tools, while others are Weapons, Accessories, Potions, or Mount- or Pet-summoning items.

Wooden Crate.png Crates
Crates are grab bag-type items that can each contain random loot. They can be right-clicked from within the player's inventory, which will unload their contents. Rarer Crate types contain more valuable loot. Each Crate type can be stacked up to 99 in a single inventory slot.

Tin Can.png Junk
These items have no use or coin value. They can each be stacked up to 99 in a single inventory slot. You will only "catch" these if you fish from a pool of insufficient size or with too low of fishing power (See Notes).

Mechanics
Lava > Honey > Corruption = Crimson > Hallow > Snow > Jungle > Mushroom > Ocean > Forest(including sky, surface, underground, cavern, etc.). Ocean > Mushroom > Corruption > Crimson > Jungle > Snow > Hallow > Others , drastically different from what applies to fishing. That may account for why you failed to fish some quest fish. (For example, you stand where Jungle and Snow overlaps, so you will hear Jungle music but harvest Tundra catches.)
 * Some biomes override other biomes. The biome order for fishing is:
 * NOTE: 1. Possible catches determined by biomes have different priorities from how the music plays. The background music of Terraria is misleading because its priority for music is:

2. There is inconsistency in the mushroom biome criteria. Note that 200 mushroom tiles is considered valid when it refers to fishing, while for other uses 100 is mostly enough.
 * Additionally, each biome has its own list of catches that each occupy "rarity slots". Each fishing attempt yields a particular slot. When fishing in overlapping biomes the higher-priority biome's catch occupying that slot will be caught. A fish from the lower-priority biome will only be caught if the higher-priority biome(s) has no fish occupying that rarity slot.
 * Most quest fish occupy the "uncommon" slot, with the exceptions of the Mirage Fish and Pixiefish, which are "rare". However, quest fish have higher priority within their native biomes than other fish.
 * The Ocean overrides all lower priority biomes and defaults to catching Trout. All other biomes default to catching Bass.

Tips

 * A good way to grind for Lightning Bugs is to either convert a large slab of land to Hallow, or one can dig a large hole (lined with dirt) and convert it to Hallow.
 * A good way to grind for Bait is to create a jungle farm, to allow and break the plants that grow, due to the high odds of getting bait per plant. Possible drops are Grubby, Sluggy or Buggy.
 * The most reliable way of obtaining Bait seems to be fishing in a surface forest, at night, close to NPCs. Staying still and restricting the spawns to critters will result in a lot of Fireflies spawning, and if alternating fishing and catching it's easy to end with dozens more bait. Water Candles and Battle Potions can be used to increase the spawn rate of critters, while the NPCs still prevent enemy spawns. Alternatively, if one obtains Flower Boots from a Jungle Shrine, they can stand on grass with a yoyo or flail and have the plants spawned by the boots be constantly destroyed, generating many worms and grasshoppers.
 * There are a total of 16 different fishing locations that can yield distinct catches: Surface: Forest, Ocean, Jungle, Corruption, Crimson, Hallow, Snow, Honey; Underground: Forest, Snow, Hallow, Jungle, Mushroom; Cavern: Snow + Hallow/Corruption/Crimson; Floating Island; Lava (any Layer).
 * Since quest fish cannot be fished or picked up when that same quest fish is already in the player's inventory, duplicate quest fish can be saved in Chests or other storage items, which can be useful since quests often repeat. Duplicate quest fish can however be placed in a player's inventory manually by moving them from Chests afterward.
 * An easy pre-hardmode way to tell if it's a full moon, and thus an ideal night to fish, would be to use a Deathweed's blooming as an indicator. A Deathweed only blooms under either a full moon or a Blood Moon, therefore -unless a Blood Moon is currently occuring- if the plant blooms when placed in a Pot, it means the Moon is full.

Trivia

 * The Neon Tetra and Golden Carp have no use, aside from their coin value. The Golden Carp is especially valuable at.
 * The Clownfish quest description is a reference to the 2003 Pixar film, Finding Nemo.
 * The Bumblebee Tuna is a reference to Ace Ventura: When Nature Calls. In a scene where he comically botches the Wachati tribe's greeting "Bumbawe Atuna" by instead saying "Bumblebee Tuna"..
 * The Batfish quest description is a reference to the iconic Batman Theme.
 * The Prismite fish sometimes can be caught in ponds in Mushroom Biome (it's unknown whether this is a bug or not).

History
Pêcher 낚시