The wait is finally over. The giant, imposing door in the Lava Basin has creaked open, and it isn't just a new room—it’s an entire ecosystem. Whether you’re hunting the legendary Rainbow Shark or just trying to figure out why a scientist needs "Mechanical Cores," this is your definitive field guide to the Fish It expansion.
Breaking Down the Lava Basin Door
To even set foot in the new zone, you have to satisfy the Magma Fisherman.
- The Requirement: You’ll need to grind the magma pools. Catching high-rarity fish like the Blueflame Ray (Mythic, 1 in 93k) is usually the trigger.
- The Reward: Once the door opens, you gain access to the Ancient Jungle, a neon-soaked cave filled with new mechanics and high-value materials.
Mining & Crafting: The New Meta
For the first time in Fish It, your rod isn't your only tool. You’ll need a pickaxe to harvest the crystals growing in the Ancient Jungle.
Veilshard: A rare, glowing purple mineral mined in the Ancient Jungle used for high-tier Charm recipes.
New Materials Table
| Material | Rarity | Source | Primary Use |
| Veilshard | Rare | Purple Crystals | Winged Charm |
| Cave Crystal | Common | Green Crystals | Basic Crafting |
| Embercrux | Exotic | Lava Fishing | Advanced Charms |
| Pyrafruit Relic | Uncommon | Jungle Floor | Quest Progression |
How to Craft the New Charms
Locate the Crafting Bench in the laboratory area to buff your gear. These charms are game-changers for late-game efficiency.
- Winged Charm: Gives a +10% Luck boost and +1.1 Reel Speed. Essential for the Comet event. (Requires: Rope, Driftwood, Veilshard).
- Oculus Charm: Increases visibility for rare fish silhouettes.
- Anchor Charm: Helps stabilize your line in turbulent waters.
Scientist Scavenger Hunt: All Mechanical Core Locations
The Lead Scavenger Hunt Scientist in the lab won't help you track the comet until you find his 4 Mechanical Cores. Here is exactly where they are hidden on Fisherman Island:
- Tropical Grove Tunnel: Tucked inside the dark tunnel passage.
- The Hillside House: Check directly behind the blue house on the cliffside.
- The Small Grassy Isle: Located on the tiny island near the main docks.
- The Rock Cover: Hidden behind a large boulder near the wooden shack.
The "Secret Secret" Rarity: The Rainbow Shark
Once the cores are installed, the Telescope becomes active. You can see a massive Comet approaching the island in real-time.
What We Know About the Comet:
- New Rarity: The bulletin board shows a silhouette for a "Secret Secret" fish (expected to be the Rainbow Shark).
- Rarity Odds: Listed as 1 in ???, making it potentially the rarest catch in the game.
- The Scientist's Warning: "It's going to attract something very... very big."
Secret Secret: An ultra-exclusive rarity tier that only appears during specific world events or astronomical cycles.
Frequently Asked Questions
How do I open the Lava Basin door? You must fish in the magma pools of the Lava Basin and catch high-rarity fish like the Blueflame Ray to trigger the Magma Fisherman.
Where are the Mechanical Cores located? The cores are hidden in the Tropical Grove Tunnel, behind the blue house on the hill, on the small island near the docks, and behind a rock near the wooden shack.
What does the Winged Charm do? The Winged Charm increases your Luck by 10% and your Reel Speed by 1.1, making it highly effective for rare fish events.
How do I get Veilshard? Veilshards are obtained by using a pickaxe to mine the rare purple crystals found inside the Ancient Jungle.
What is the rarity of the Rainbow Shark? The Rainbow Shark is classified as a "Secret Secret" rarity, which is an ultra-exclusive tier with "1 in ???" odds.
Where is the Crafting Bench? The Crafting Bench is located inside the laboratory area within the Ancient Jungle.
