The Halibut Harpoon is more than a fishing rod. It hides a boat customization trick, a secret Legendary skin from Dr. Monty, a weight-boosting mini-game, and a full harpoon gun mode that most players never trigger. Here is how each of those systems works and the exact numbers behind them.
Quick answer: Feed a mutated pufferfish to the Pufferfish Boat to reskin it, gift Dr. Monty a self-caught Aether Pufferfish for the Legendary Pufferfish Harpoon skin, land 15 harpoon hits for a 1.7x weight multiplier, and press Q to switch into gun mode to catch whole schools.
Reskin the Pufferfish Boat with a mutated pufferfish
The Pufferfish Boat can copy the look of any mutated pufferfish you own. Walk up to the boat with a mutated pufferfish in your inventory and feed it into the boat’s mouth. The boat’s skin changes to match that mutation, and the fish is not consumed in the process.
The effect is temporary. Despawning and respawning the boat resets its appearance back to default, so you will need to feed it again each time you spawn it.
| Boat | Speed | Steering | Acceleration |
|---|---|---|---|
| Pufferfish Boat | 2505/ps | 80° | 0.215/ps |
| Neon Arrow Boat | 2705/ps | 80° | 0.225/ps |
Unlock the Legendary Pufferfish Harpoon skin
The secret skin comes from Dr. Monty in Monty’s Lab, and it only accepts a pufferfish you caught yourself. A fish traded from a friend will not work because the game checks whether your username is attached to the catch.
Received Pufferfish Harpoon (Halibut Harpoon) Skin, which is how you know the trade worked.
The skin is interactive. Its color shifts dynamically based on your “Halo Color” setting in the game menu, so you can tune its appearance without changing anything else.
The 1.7x weight multiplier from harpoon hits
When you reel in a fish, 15 to 35 harpoons home toward random spots in the mini-game, each marked by an exclamation point. Every harpoon that lands adds +1% progress, and each landing harpoon has a 5% chance to crit for an extra +1%. A fresh wave of 15 to 35 harpoons also fires every 5 seconds.
The reward for accuracy is a weight bonus. Landing at least 15 harpoons on the fish and the bar multiplies the final fish weight by 1.7x. That stacks on top of the rod’s built-in +20% weight boost and its high mutation odds, which include a 20% chance each for Bathyal (7x), Thalassic (9x), and Hadal (11x), rising to a 30% chance for Hadal on a perfect catch.
What the harpoon stats do
Four stats drive the harpoon’s behavior, and each one has a cap that limits how far bait can push it. The base values sit near the bottom of each range, so bait is what moves the numbers up.
| Stat | Controls | Base | Cap range |
|---|---|---|---|
| Universal Luck | Harpoon crit chance | 5% | 5 to 10 (min 1%, max 10%) |
| Preferred Luck | Minimum harpoon count | 15 | up to 25 |
| Resilience | Harpoon damage / progress | 1% | 1 to 5 (max 5%) |
| Lure Speed | Harpoon interval | 5s | 1 to 5 (min 1s, max 5s) |
How bait rarity changes the harpoon
Beyond raw stats, the rarity of the bait you equip adds a separate effect. Some of these are useful, and one is purely cosmetic, so check the rarity before a serious run.
| Bait rarity | Effect |
|---|---|
| Common / Trash | Shoots confetti instead of harpoons |
| Uncommon | Sets Minimum Harpoon Count to 25 |
| Unusual | +5% Shiny / Sparkling chance |
| Rare | 1.25x final fish weight (+25% sell value) |
| Legendary | +10% chance for the Royal mutation (9.4x) |
| Mythical | +10% progress carried over per catch |
| Exotic / Secret | +1% progress per landing harpoon on Progress Locked fish |
Individual baits also carry their own stat lines that feed into the four core stats above. A few examples show how different they are.
| Bait | Preferred Luck | Universal Luck | Resilience | Lure Speed |
|---|---|---|---|---|
| Deep Coral | 150 | -10 | 50 | -10 |
| Instant Catcher | — | — | — | 50 |
| Neuro Slug | 120 | 30 | 15 | -30 |
| Flakes | 85 | — | -3 | 10 |
Note: the rod has a Control cap of 0.15, and Snail bait is the one exception that can bypass that limit.
Switch to Harpoon Gun mode with Q
Press Q on desktop to convert the Halibut Harpoon into its gun variant. In gun mode, shooting a school of fish catches the entire school in one go, which pairs directly with the roaming fish the harpoon guns were built around.
The mode also helps you stay underwater longer. Reeling in a fish while submerged in gun mode replenishes 5% of your oxygen per catch, letting you chain deep-water grabs without surfacing as often. The gameplay demonstration ends with a Scylla pulled in using the gun, showing the mode handles high-tier catches as well as schools.
Put together, these systems make the Halibut Harpoon one of the most layered rods in Fisch. The boat trick and the interactive skin are pure flair, but the weight multiplier, bait scaling, and gun mode are the parts that actually change what you land.
