On mobile, and 3ds versions, Duke Fishron and Ocram are the 2 final bosses because the Moon Lord is not implemented in those versions.
Attacks: First stage:
- Charges at a player. (5 times in a row.)
- Detonating Bubble spray (The bubbles can be destroyed by weapons or projectiles.)
- Summons two aqua rings. When the rings touch the ground, they transform into sharknadoes.
- A sharknado is a huge tornado that throws a lot of Sharkrons at any direction.
Second stage: (His skin becomes a darkish green and eyes glow yellow.)
- Charges at a player again. (Three times in a row.)
- Spins quickly and releases sharknadoes and homing bubbles.
- Shoots one homing aqua ring. If this ring hits a player, then a larger sharknado ("Cthulhunado") will spawn beneath them, spawning more Sharkrons than a stage one sharknado.
Third / Desperate stage: (Exclusive to Expert Mode, only activates at very low health)
- Background will turn blue with thick fog, rendering Duke Fishron mostly invisible.
- Will charge at players every few seconds while remaining mostly invisible, only appearing after finishing a charge.
- Reaches maximum speed and damage is lowered.
A very good defensive strategy that doesn't require many rare items would be to craft 2 Gravitation Potions, have around 70 defense, acquire the Terra Blade and some Warding accessories. Simply activate one potion and repeat moving from the top of the map to the sea level while swinging your Terra Blade. When Duke Fishron reaches stage 2, the player must try to avoid moving too far away from the boss as it will make it despawn. To do so, while the boss uses one of the spells that makes him stand still, gravity must be inverted. Using this method and some acceptable dodging skills, the player should be able to take out the boss in a maximum of 5 minutes. Without having to farm any Key Molds, it is a very general and effective way of taking down the boss. To defeat him with minimal damage, have some Greater Healing Potions prepared, decent defense (60 or above), and Vampire Knives. Vampire Knives and 60 defense aren't needed if the player has high DPS magic weapons. With the Spectre Hood Set, it's best to use high DPS magic weapons instead of Vampire Knives. It is also best to get a Hoverboard, or build a skybridge with Asphalt Blocks; note that in the PC version this bridge may not lead out of the Ocean biome or he will become enraged (all stats tripled) and virtually impossible to defeat. Do not start using the healing potions before it is enraged. While the boss is charging, shoot towards him with Vampire Knives, while moving away from him with a Hoverboard or skybridge. This works quite well as the Hoverboard is almost as fast as the boss when charging. It is important to keep moving away while shooting when the boss is shooting bubbles or using the sharknado attack, as it spares more time for the player to heal. When enraged, the player might find it a bit harder to avoid its attacks, thus allowing the Greater Healing Potions to come in handy.
Another strategy that is very simple, is to acquire the Piranha Gun and simply kite him around on an asphalt surface, preferably around 2000 blocks long. With decent dodging, high defense and a couple of health potions in reserve, the fight is easy.
Another good strategy (one that unfortunately requires a lot of farming) involves using a skybridge with Heart Statues and Campfires along it. Will Need:
- Arena: Skybridge (Platforms)
- Armor: Beetle Armor (with Shell)
- Weapons: Death Sickle; Possessed Hatchet (can be traded for Paladin's Hammer or Bubble Gun later on)
- Potions: Ironskin Potion, Regeneration Potion, Swiftness Potion, Gravitation Potion, Greater Healing Potion, Pumpkin Pie, Flask of Ichor, Hunter Potion
- Equipment: Ankh Shield; Moon Shell; Hoverboard; Frostspark Boots; Master Ninja Gear
- Misc: Heart Statues, Campfires
Dodge the Duke's attacks as best as possible. During the dashes before the Bubble attack, use the Death Sickle or the Paladin's Hammer. During the dashes before the sharknadoes, use the Possessed Hatchet or the Bubble Gun. When he reaches Phase 2, only use the Death Sickle or Paladin's Hammer, and dodge as best as possible. Use the Heart Statue when needed.
Another strategy requires use of the following:
- Arena: None specific
- Armor: Spectre Armor (with Hood)
- Weapons: Razorpine
- Potions: Greater Mana+, Greater Healing+
- Equipment: Hoverboard/Spooky Wings, Lightning Boots, Master Ninja Gear, Mana Flower - All reforged to Warding
Using the Razorpine, circling Fishron while constantly aiming at him will cause massive damage; this should leave him dead within around 30 seconds.
Once the player has obtained the Flairon, the battle becomes significantly easier; running at top speeds using Asphalt Blocks or Minecart Tracks while auto-reusing the Flairon deals heavy damage.
- If the player leads or spawns Fishron somewhere other than the Ocean biome, he will immediately become enraged regardless of how high his health is.
- It's the only boss that uses invisibility (similar to a Pigron) to pass through walls.
- This is the first ocean boss in Terraria.
- The "sharknadoes" he shoots are a reference to the movie Sharknado.
- Duke Fishron may despawn when a player gets too far away.
- Unlike other bosses, Duke Fishron only drops a measly 1 after being killed.
- His name is a portmanteau of "fish" & "dragon".
- There is a quote from the Truffle that goes: 'Have you seen any pigs around here? My brother lost his leg to one.', referencing the Duke Fishron, which is based on the Pigron monster; this may indicate that the Truffle Worm is the Truffle's brother.
- Use life sucking weapons like Vampire Knives to get as much health as you can while Duke Fishron is in his second form.
- The name and the look of the Fishron appears to be heavily based on the underground Hallow, Crimson and Corruption monster Pigron.
- Duke Fishron bears a resemblance to a mutant creature from the TV show Futurama (season 2 episode 5).
- It is possible to summon Duke Fishron with the Hotline Fishing Hook by finding a large pool of lava and using the Truffle Worm. However, he will be enraged if spawned this way.
- Maximum distance between the player and Fishron required to despawn him increased.
- Now drops a Treasure Bag in Expert Mode.
- Another stage of attack is added in Expert Mode.
- Now becomes enraged when leaving the Ocean biome.
- All of Fishron’s weaponry now sells for 5 . This will fix the low prefix costs.
- Fixed a bug where Duke Fishron did not drop Greater Healing Potions when dying.
- Fixed a bug where trying to use multiple Truffle Worms while line is pulled would make numerous Fishrons appear.
- Fixed issues where the Truffle Worm would be consumed without summoning Duke Fishron.
- Only one Duke Fishron can be summoned at a time. The bobber will not bob if one is already alive.
- Added to the game.