Guide:Duke Fishron strategies

Duke Fishron is a tough flying fish/Pigron boss with very high movement speed and high damage, making it the one of the most difficult bosses in the game. It is advised to use life-draining weapons on him and high movement speed.

Terrain preparation
Note: As of 1.3.0.1 skybridge arena will most likely not work due to changes in Fishron's AI. Make a very long skybridge to fight Duke Fishron. Somewhere around 700-1000 should be enough. Asphalt blocks are highly recommended. The basic goal while fighting Duke Fishron is to run away quickly while attacking constantly. Alternatively, you can build a very long zigzag pattern of diagonal blocks.

Multiple layers may assist in avoiding his attacks, though it's not entirely necessary.

If one desires not to spend time making an arena, they can use a Water Walking Potion or Water Walking Boots (Recommended) instead.

Duke Fishron is capable of running away.

For Desktop players, it is advised to make arena over the Ocean (without exiting the Ocean biome, since Duke Fishron would get enraged, making it nearly impossible for the player to beat him), consisting of several long platform layers. Heart and star statues, as well as campfire and/or Heart Lanterns can be used to boost one's combat capabilities.

One could also use a minecart to outrun him in limited space above ocean biome.

Armor

 * For magic it is advisable equip the Spectre Armor with the Spectre Hood to drain health, or Spectre Mask if one desires more damage.
 * For melee characters the Beetle Armor with Scale Mail are recommended as they give decent defense paired with attack buffs which stacks as the player damages the boss or the Sharknados. If the player desires high defense, Beetle Armor with Shell or Turtle Armor are recommended.
 * For ranged characters the Shroomite Armor is highly recommended.
 * For summoner characters having both the Spooky Armor and the Tiki Armor is highly recommended, using the Spooky Armor to summon all but the last minion, and wearing the Tiki Armor for the additional minion and higher defense.
 * If the Moon Lord has been defeated, armors constructed from Lunar Fragments may be preferable: Solar Flare armor for melee characters; Vortex armor for ranged characters; Stardust armor for summoners; and Nebula armor for magic or, due to the booster buffs, possibly for any character.

Summoner

 * Due to the ability to always have at least one minion, or two with access to a Bewitching Table, summoning a minion prior to Duke Fishron may be helpful. However, due to his significant defense, weaker minions should be avoided; and due to his extreme speed, slower minions or those who use slower projectiles will be similarly ineffective. The Optic Staff, Xeno Staff, and especially the Deadly Sphere Staff can be quite helpful, where the otherwise impressive Stardust Dragon can have difficulty keeping up with the Duke.
 * Maximize summon damage with buffs from food and potions, armor, and accessories when summoning minions, as the minions retain the increased damage even if the equipment is removed, until the minions are unsummoned or replaced.

Magic

 * Homing weapons like Bat Scepter or Spectre Staff will let you focus on dodging.
 * Rapid weapons like Razorpine or Leaf Blower, rapidly recover health, which is extremely helpful for the fight. Razorblade Typhoon if you have already defeated the Duke, will let you focus on dodging as well, if you have decent enough aim. The only problem with Razorblade Typhoon is that the homing shots cannot keep up with him when he is rushing.
 * It is possible to outheal Duke Fishron if one has equipped a Mana Flower, A few stacks of Greater Mana Potions (Can get from Wizard), and a high rate of fire Magic Weapon (the Laser Machinegun proves useful in this situation).
 * The Golden Shower spell is helpful as it reduces his defense.
 * If you have good aim the Inferno Fork does a lot of damage.
 * The Blizzard Staff is very good for attacking while he is stationary.
 * Avoid using magic weapons like Magnet Sphere, Wasp Gun and Rainbow Gun as Duke Fishron's extreme speed will render these attacks nearly useless.

Melee

 * Vampire Knives are very useful for stealing life combined with decent damage, however the life steal effect seems to work better on his second stage.
 * Flask of Ichor is useful to slightly lower Duke Fishron's defense.
 * The Influx Waver is a better choice if you have defeated the Martian Madness event and obtained it from the Martian Saucer boss.
 * The Terra Blade also performs well, though not usually as well as the Vampire Knives.
 * Constantly throwing the Paladin's Hammer or Possessed Hatchet while flying around can defeat him quickly.
 * A stack of Bananarangs are good against the boss for its rapid throw and return. They do not home in on the boss, so speed is key.
 * The Eye of Cthulhu is the best yoyo that can be used by yoyo users, before defeating the Moon Lord.

Ranged

 * The Snowman Cannon is powerful against him, if you have defeated the frost moon.
 * The Chain Gun, if you have beat the frost moon, or Megashark, paired with Chlorophyte Bullets do very well; as these weapons have homing properties little aim will be required leaving the player to focus on dodging the boss.
 * The Piranha Gun attaches to Duke Fishron and deals continuous damage, so the player can focus on dodging Duke Fishron's attacks.You must do this at the start of the fight, or else he will be too fast for the piranha to latch on.
 * Ichor Arrows or Ichor Bullets will reduce his defense.
 * The Chlorophyte Shotbow with Venom Arrows is useful. Chlorophyte Arrows are good, but piercing weapons give the boss a 1/6 second immunity, and the other arrows may not hit him. It's best to use none piercing arrows, preferably Venom Arrows because of their high velocity. (Note, 1/6 of a second is barely any time, and other piercing weapons are still effective, but that 1/6 of a second is barely long enough to only allow 1-2 Chlorophyte Arrows hit, instead of all five.)
 * The Stynger is very effective.
 * Using a Phantasm with Holy Arrows can make the fight extremely easy, to the point where you can kill the boss within less than a minute and without taking major damage. This will be efficient even without Vortex armor or end-game accessories, although will only be possible if the player has already defeated the Lunar Events (which are considered easier to beat than Duke Fishron by some) to acquire the Vortex Fragments necessary to craft the bow.
 * A Tactical Shotgun with Chlorophyte Bullets is good for its wide spread, automatic firing, low ammo consumption, and homing ability.

Additionally

 * The Rod of Discord isn't a weapon, but helps with dodging.

Accessories
A must is Hoverboard and Lightning Boots or better as primary choice. They are both fairly easy to get at this point. If you have defeated Duke Fishron, Fishron Wings will also help. Frog Leg can be used for more mobility. A shield will prevent knockback from Sharknadoes.

Equip accessories with damage, crit, or—if using magic—arcane, modifiers. Accessories such as the Celestial Stone, Fire Gauntlet, Sniper Scope, and emblems will also greatly improve damage output. Warding accessories can be used if the player desires extra defense.

Cross Necklace or Star Veil is recommended as the boss speed might cause several heavy hits on characters should the boss catch the player. The Sharknados may also flank the player hitting them consecutively especially on Duke Fishron's second phase.

Characters with Spectre Armor should consider using Magic Cuffs or Celestial Cuffs, as the damage dealt by Duke Fishron's attacks will often times completely restore their MP, allowing them to attack constantly while restoring HP. Care should be taken as the boss' high attack can make quick work of reckless players.

Magic users should also consider the Mana Flower.

If you have difficulty dodging his charges and/or bubbles, invest some time in getting a Tabi or Master Ninja Gear.

Charm of Myths will both allow for increased regen and reduced time for the Potion Sickness debuff.

The Cosmic Car mount is a good replacement for wings and can be better as it provides infinite air time.

Potions and Buffs
As with any other Hardmode boss, it would be useful to prepare the following potions:
 * Greater Healing Potions are highly recommended, though not entirely necessary with life-draining weapons.
 * Greater Mana Potions are recommended for magic users.
 * Regeneration Potion and Ironskin Potion to survive. Two of each will last enough.
 * Endurance and Lifeforce potions for even greater survivability.
 * Pumpkin Pies will likely last the entire fight, and it's easy to craft.
 * Swiftness Potion helps you a lot to evade the Duke and its attacks.
 * Wrath and/or Rage potions for a boost in damage output.
 * Magic Power Potion and the Crystal Ball's Clairvoyance buff for magic users is recommended.
 * If a player has no arena, they can just use Water Walking Potions.
 * Gravitation Potions can free up an accessory slot, but it's recommended to use Featherfall Potions with them.
 * Melee characters that are good at dodging can use the Tipsy debuff.
 * if you are facing him at night, a Shine Potion and a Night Owl Potion will help a lot so that you don't have to worry about visibility.

The Battle
Duke Fishron will attack in three different ways during his first stage. He will try to charge into the player five times before summoning one of two projectile attacks: Duke Fishron will blow about 20 bubbles that follow the player at a medium speed. They explode and dealing damage on contact. These bubbles can be destroyed via any attack or projectile, however they can be hard to hit. In his other projectile attack, he will summon some liquid blobs by waving his fins that fall through platforms until they travel 1.5x the vertical size of the screen or impact with blocks. Then they will create 'Sharknadoes'- giant water tornadoes that summon several Sharkrons. The Sharkrons have limited flight range, are destroyed on impact with blocks, and can be killed by the player. After a projectile attack, he will proceed to repeat the cycle.

Basically, just shoot him while running around, jumping, flying, and go back to avoid getting hit. Don't run too far or he may despawn. A good way to avoid Duke Fishron's attacks is to fly up when Duke Fishron starts dashing, and drop when he gets close to you, which is usually on the third dash. When it uses detonating bubbles is not much of a problem if you run and dodge its attacks. Tornadoes may be painful obstacles, but you can recover your health quickly if given enough time, and Sharknados are not a problem as they are more likely to die very quickly. Focus on popping bubbles when they spawn. Remember, KEEP MOVING AND KEEP ATTACKING, otherwise you will die.

When Duke falls below 25,000 health, he will stay stationary for a second, then his eyes will glow as he enters his second stage. His damage, and speed increase significantly, however his defense drops to 40. His lunges become faster, and are only performed three times instead of five before executing one of his projectile attacks, which are also upgraded. The detonating Bubbles are now fired while Duke Fishron flies in quick loops, which leave a trail of the bubbles behind. Instead of several blobs that create Sharknadoes, he will summon one blob that chases the player, creating a powerful 'Cthulunado' upon contact. It will summon twice as many Sharkrons as in the first stage.

In Duke's second form, you have to be more careful as detonating bubbles spray everywhere. Also, keep moving as he's extremely fast and follows you. But the most important thing is to avoid bigger tornadoes because they can do massive damage-up to 150 or more, even with better armor. On the other hand, you also have to fire more accurately because Duke Fishron moves and dodges faster than before, and sometimes it can evade homing projectiles. Like before, keep moving and keep attacking.

Care should be taken even after the boss has been defeated as he might summon a last set of Sharknadoes, which can kill an unsuspecting player. Additionally, the loot can fall inside the tornadoes that Duke Fishron may have created, forcing the player to wait if they don't want to take damage.

Minecart Strategy (without skybridge; works on 1.3)
This strategy differs from others in that it doesn't use skybridge, replacing it with looped minecart track above the ocean, so the player won't have to deal with his enraged behavior. It does, however, need some more work than other ones, especially when building arena.

Materials

 * 600-1200 normal minecart tracks for building loop + 2 booster tracks
 * 10-30 Greater Healing Potions
 * Any kind of hammer

Weapons
Ranger: Mage: Melee:
 * Tactical Shotgun, Uzi or Megashark with Chlorophyte Bullets
 * Chlorophyte Shotbow with Venom Arrows
 * Spectre Staff
 * Shadowbeam Staff or Heat Ray
 * Leaf Blower
 * Possessed Hatchet
 * Scourge of the Corruptor
 * Vampire Knives

Arena Preparation
The essence is to make looped minecart track approx. 60 tiles above Ocean itself. It should consist of at least 600 tiles; while shape is pretty loose, it should have at least two places in which player drastically changes altitude, as well as at least 100 tiles long flats. One should also make a "Starter" - a short molo with boosters, from which player will summon Duke Fishron and quickly escape to the loop. Placing Campfires and Heart Lanterns could prove to be difficult, but will help player if something goes wrong. It should be noted also that arena shouldn't exceed Ocean biome.

Execution
When everything's done, player should sit in a minecart on "Starter" and summon the Fishron. As soon as it's done, one should quickly go to loop (boosters will help). At this point, everything that remains is to shoot Fishron while maintaining speed on track, healing a/o replenishing mana when needed. Some tips:
 * Use homing weapon, especially if arena is pretty large. Fishron will be most time off-screen, and high speed will often change directions you're facing.
 * Though stock minecart shouldn't be used, Mechanical Cart is not a good choice. Even though with it provides defense bonus, as well as speed to avoid Fishron's charges, it will propably outrun him so much that he will despawn, what is especially possible on larger arenas. Higher speed means also that You will more often run into Sharknados.
 * Try to make arena consisting of approx. 800 tiles, but don't make it horizontally-long. If You do so, Fishron will frequently run into You, and Cthulunados in his second stage will quickly kill You, as there won't be any way to dodge them.