How to Fish Tuna Boss: Island 4 Mini-Boss Guide

The Tuna is tied to Island 4, so you need to reach that point in the island chain before this fight is available. Once you are there, head to the island's shop and buy the Professional Boss Lure, which is the item that summons the boss when you fish with it. See our lure guide for how boss lures fit into your overall tackle setup, and the Island 4 page for the island itself.

The most important preparation step happens before the lure ever touches the water: equip your weapon first. The Tuna enters combat immediately when it is pulled out of the water, and players who cast with empty hands lose the opening seconds of the fight scrambling for their gun. If one dock does not work, try the island's other water edges.

The Tuna's signature move is a high-speed charge, and the nasty part is that it predicts your movement direction. If you simply keep running in a straight line, it aims where you are going and clips you mid-sprint. Panic-dodging early has the same problem, because the boss reads your direction and adjusts.

The arena makes this worse. Island 4 is a small area, so there is far less room to sidestep a fast charge than you might be used to from open-water fights. That combination of predictive aim and tight space is why the Tuna feels so much harder than its mini-boss label suggests.

The good news is that the charge is also its weakness. When the Tuna misses, it overshoots and leaves a recovery opening, and that window is where all of your damage should happen. Focus on the pattern rather than counting hits.

The reliable strategy is a loop built around the Tuna's predictive charge. Run it like this:

1. Buy the Professional Boss Lure from the Island 4 shop and equip an upgraded weapon before casting.
2. Cast and reel the Tuna in; combat starts the instant it leaves the water.
3. Bait the lock-on by moving slightly to one side, committing just enough that the Tuna aims that way.
4. Dodge by quickly reversing direction so the charge overshoots you.
5. Punish the miss by shooting during its recovery opening.
6. Repeat the bait-dodge-punish cycle until the Tuna goes down.

For weapons, the sources recommend a fully upgraded Shotgun or Sniper Rifle. The Shotgun deserves special mention because Island 4's cramped arena keeps the Tuna close, which is exactly where a Shotgun shines. If you prefer the Sniper Rifle, use the recovery window to land high-damage shots from range after each missed charge.

In multiplayer the same loop applies, and lobbies support up to 8 players after Patch 1.0.4, so a co-op crew can focus fire during every opening. Just make sure your teammates understand the bait step, because one player feeding the Tuna a free read on their movement ruins the rhythm for everyone.

A defeated Tuna can be sold, and on a tight budget that is tempting, but the body doubles as the key quest bait for summoning the Albatross. Selling it before you have progressed that quest chain will stall your main story until you can get another one.

The next step is simple: place the defeated Tuna on the ground to trigger the Albatross quest chain on the same island. Because that chain follows right after the boss fight, smart players stock up before ever casting the Professional Boss Lure. Bring enough food and ammunition for two back-to-back fights, not one. Whatever its sell price is, it is not worth delaying the Albatross.

A Steam Community guide nicknamed the boss "Batman" documents an alternative kill: summon the Tuna with the Professional Boss Lure as usual, then blow it up near the shop area with a large amount of TNT. The method was tested in a two-player session and reportedly kills the boss quickly.

Treat this as a novelty, not a replacement for the standard strategy. It costs a fortune in TNT, it is completely non-standard, and anything that depends on explosive physics can change behavior from patch to patch. How to Fish is updated frequently, with Patch 1.0.9 live as of Aug 25, 2026, so check the updates page if the trick suddenly stops working. For a first kill, the bait-dodge-punish loop above is cheaper and far more consistent.

• Casting with your weapon unequipped. The fight starts the instant the Tuna surfaces, and fumbling for your gun wastes the safest opening.
• Running in a straight line. The Tuna predicts your direction, so steady sprinting just aims it for you. Bait the lock-on first, then reverse.
• Selling the body. The Tuna is the Albatross quest bait; the money guide has better ways to earn that do not stall your story.
• Summoning underprepared. The Albatross chain follows immediately, so bring food and ammo for two fights.
• Leaning on the TNT trick for your first clear. It is expensive, physics-dependent, and the standard dodge-and-shoot loop works on every patch.

Once the Tuna is down and the Albatross chain has started, browse the full bosses list to plan your next fight, and keep that Shotgun upgraded.