Defeating the Mutated Bowhead Whale (Lava Whale)

What Is the Mutated Bowhead Whale?

The Mutated Bowhead Whale — often called the Lava Whale — is the final boss of How to Fish, the physics-driven fishing-and-shooting game from Dazed Games. It appears only on the fifth island, the Volcano, and it is the one fight in a run that can actually stop you. You do not walk into it directly: you first catch and kill a regular Bowhead Whale, then throw that carcass into the volcano to spawn the mutated, lava-covered version.

How to Spawn the Mutated Bowhead Whale (Whale-into-Volcano Sequence)

The scientist in the yellow hazmat suit is your military contact on the Volcano island. There is no separate creature to hunt first — the mutated whale is created by feeding a beaten regular whale to the volcano.

1. Give the hazmat scientist any five Volcano-native fish. Throwing Dynamite into the water and scooping up the results is the quickest way to gather them. He gives you the Fish Bucket in return.
2. Equip the Fish Bucket as bait and reel in the Bowhead Whale. This starts the first whale fight. (The Scientific Lure that catches those five fish costs $500.)
3. Kill the regular Bowhead Whale. It charges across the arena and launches into the sky before slamming down on your position, so run the moment it shoots upward, then dodge, shoot, and eat to heal. This version is far weaker than the mutated one.
4. Pick up the dead whale and carry it to the volcano summit using the wooden planks. Keep the body — do not sell it, because the carcass is the trigger for the final boss. (If you drag it too far from where it spawned it can despawn, so let it catch up rather than racing off.)
5. Throw the carcass into the lava pool at the summit. This immediately spawns the Mutated Bowhead Whale.
6. Drop back down to the military base immediately. The flat terrain there is easier to fight on, and it is where you should have already stashed your extra cooked fish.

Best Loadout & Prep (Before the Fight)

This boss is won during preparation, not during the fight itself. A couple of clean hits from the mutated whale can kill you, so raw damage output matters less than keeping your health topped off and never standing still. Treat the regular whale and the lava whale as one continuous encounter — there is no chance to restock once the final boss is live.

• Fully upgraded Assault Rifle — your main damage source for both whales. Get every available upgrade and attachment before summoning (Laser and Suppressor give steady hip-fire accuracy and unlock the Fully equipped achievement; Compensator and Red Dot Sight also help).
• Lava-cooked fish (large stock) — your only healing. Volcano lava cooks fish at a flat 1.5× value with no timing window. Fill your inventory and drop spare piles near the military camp so you can refill between phases.
• Dynamite — blows up four or five fish at once, the fastest way to build both your food pile and the bait fish you hand to the scientist.

How to Beat the Mutated Bowhead Whale (Two Phases)

There is no clever trick to this fight — it is a stamina test. Keep your distance, pour steady assault-rifle fire into the boss whenever it is not mid-attack, and heal every single time you take damage rather than waiting until you are low. The ground is as dangerous as the whale itself.

• Roll: hold your distance and strafe around it in a circle.
• Stomp: move out from under it the instant it winds up.
• Lava pools: watch the floor and dodge the pools as carefully as the boss.
• Lava meteorites: keep moving across the arena so the shots miss.

Phase two is where most runs fall apart. The whale becomes far more aggressive, stomps almost constantly, and periodically leaps into the sky to rain attacks down on your position. Keep moving and reposition the moment it launches. Constant circular, semi-random movement is what keeps you out of the projectile lines while you chip its health bar down.

Do not try to escape the arena by boat — pulling the whale too far from the volcano despawns it and resets the whole fight. Co-op turns this into the manageable fight it is designed to be: one player can hold the boss's attention while the other works a firing line, and the army tent on the island makes solid cover. Some solo players fish the whale up on the bird island and peek from inside the armoury shack, where it cannot reach you while airborne.

Loot & How to Finish the Game (Whale Fin → Credits)

You know the fight is over when the on-screen notification reads "New Creature Caught: Mutated Bowhead Whale." The boss drops a Whale Fin on death, but that item alone does not end the game — you still have to return it to the scientist.

1. Pick up the Whale Fin the boss leaves behind.
2. Carry it back to the hazmat scientist and hand it over. He responds with the keys to the military boat (the RHIB), saying "great, take these keys if you want to head home."
3. Board the RHIB and start it. The military boat takes you to the mainland and rolls the ending credits, which also unlocks the We are so back achievement for finishing the game. Your existing save keeps every purchase and weapon upgrade.

Handyman Achievement — Kill It With Your Bare Hands

If you are chasing the Handyman achievement ("defeat the final boss with your bare hands"), only the killing blow has to be a punch, not the whole fight. Fight the lava whale normally with the assault rifle, then chip its health down to the thinnest sliver you dare before swapping to fists for the final hit. Brass Knuckles do not count — it must be bare hands. Because you are eyeballing that last bit of health, expect to overshoot and accidentally finish it with the rifle a few times, then just re-run the fight. Have full health before you attempt the punch, since one hit at close range can otherwise kill you. In co-op it is much easier, and if any player in the lobby lands the correct killing blow, everyone earns the achievement.

FAQ

How do I spawn the Mutated Bowhead Whale in How to Fish?
On the Volcano (5th island), give the hazmat scientist in the yellow suit any five Volcano-native fish and he hands you the Fish Bucket. Equip the Fish Bucket as bait, reel in and kill the regular Bowhead Whale, pick up its carcass, carry it to the volcano summit via the wooden planks, and throw the body into the lava pool. That summons the Mutated Bowhead Whale.

What bait does the Bowhead Whale need in How to Fish?
The regular Bowhead Whale is summoned with the Fish Bucket, which the hazmat scientist gives you after you bring him five Volcano fish (caught with the Scientific Lure, which costs $500). The Mutated Bowhead Whale is not summoned with bait at all — you trigger it by throwing the beaten regular whale's carcass into the volcano crater.

Can you beat the Mutated Bowhead Whale solo?
Yes. It is the hardest fight in the game and is won on movement and healing rather than tricks. Keep your distance, strafe, and eat a lava-cooked fish after every hit. Some solo players hook the whale on the bird island and shoot from inside the armoury shack where it cannot reach them while airborne. Co-op is much more forgiving because you can revive each other.

How do I get the Handyman achievement on the final boss?
Handyman requires defeating the final boss with your bare hands, but only the killing blow has to be a punch — you can damage it normally with the assault rifle first. Chip its health down to a sliver, then swap to fists for the final hit. Brass Knuckles do not count, so it must be bare hands, and enter the punch at full health because a close-range hit can kill you.

How many bosses are in How to Fish?
Published guides disagree. how2fish.wiki lists 11 bosses (6 story bosses that gate the next island plus 5 optional mini-bosses), verified for Patch 1.0.9. A Chinese guide lists 5 bosses (one per island). We report both because the counts differ between sources; the Mutated Bowhead Whale is the finale in every version.

Sources

All mechanics above are cross-checked against these published walkthroughs (no values were invented):

• AllThings.How — How to Beat the Mutated Bowhead Whale (Lava Whale Final Boss), updated Aug 27, 2026.
• AllThings.How — How to Throw the Whale into the Volcano and Beat the Final Boss, updated Aug 27, 2026.
• GameRant — How to Fish: How to Get the Handyman Achievement (bare-hands final boss).
• how2fish.wiki — All 11 Bosses in How to Fish, verified for Patch 1.0.9, Aug 26, 2026 (boss bait table and lure prices).

Boss health numbers vary between public field guides, so this page intentionally lists spawn, loadout, and fight mechanics only. This is an independent, fan-made guide and is not affiliated with Dazed Games.