How to Fish: Pufferfish fight, growth and poison

How to fight the Pufferfish

Keep firing while moving into clean space ahead of the Pufferfish. It rolls toward players, grows as its health falls, and starts leaving poison during its second phase. Avoid circling back through its recent trail.

The Pufferfish has 18,000 HP on Default difficulty with one player and a five-minute timer. That makes sustained damage a bigger concern than in the earlier Giant Piranha fight. Prepare your weapon before casting the Carrot.

Equipment available for the first encounter

Island 3 sells the SMG for 650, along with the Shotgun for 150 and Pistol for 50. They are options you can obtain before this fight. The Sniper Rifle first appears on Island 4, so a sniper strategy assumes a later revisit.

Get the Carrot through the Pufferfish Hunter's creature request. Resolve any active boss before fishing with it.

Watch the body as it grows

The Pufferfish's body grows progressively as HP falls. It does not wait until half health to become larger. Leave enough room to account for that growth instead of relying on the gap that was comfortable at the beginning.

It chooses a living player to follow and can change targets during the fight. In co-op, do not assume it will keep pursuing the same teammate. Its base body-contact damage is 34 before difficulty and multiplayer adjustments.

Raised ground is not guaranteed protection. The Pufferfish can jump toward an elevated player and also jumps when stuck. Choose space that lets you keep moving rather than betting the attempt on a perch.

What happens at half health?

At half health, it becomes temporarily invulnerable during a roughly three-second transition. Stop wasting shots into that interval and use the time to reposition or reload.

Keep your distance while doing so. Body collision can still damage you, and the second-phase poison checks already run during the animation. Invulnerability protects the boss; it does not pause every hazard around it.

The poison zones remain for about four seconds. Moving out stops repeated exposure, but poison already applied to your character wears off separately. Do not expect the status to disappear the instant you leave the trail.

Why co-op health looks different

Each extra connected player adds 30% of the difficulty-adjusted base HP. That is a smaller increase than the 50% used by the other bosses covered here. A teammate joining during the encounter can raise the boss's maximum and current health; leaving does not undo that increase.

Pick up the Fin

The boss drops a Pufferfish Fin. Bring it to the Pufferfish Hunter's passage request and collect the offered reward to continue.