Crimson Cavern awaits. A mutation-twisted route through Fisch’s shadowed tunnels that turns risk into revelation.
How to Get to Crimson Cavern in Fisch
To reach Crimson Cavern in Fisch, sail southeast from the main island toward the coordinates 4500, -3200. Watch for the jagged red rock formation piercing the horizon, marking the cavern’s entrance. Anchor your boat at the shallow bay just offshore, then swim through the narrow underwater tunnel lined with glowing crimson crystals. Emerge inside to find the mutation altar waiting. Bring a light source to counter the dim interior.
Finding the Crimson Cavern is easy in Fisch, but it comes after you cross the first cavern and catch a specific fish with a specific mutation. Here is the step-by-step guide that will help you get to the Crimson Cavern:
Go to Luminescent Cavern
The Crimson Cavern is located inside the Luminescent Cavern. To reach there, find all the required keystones and unlock the Luminescent Cavern in Fisch first. Go to the Mysterious Crack in Desolate Deep and submit the keystones to do so. You can also use the GPS in Fisch and go to these coordinates to find the cavern entrance: 1013, -313, -4038.
Catch Colossal Blue Dragon
Once in the Luminescent Cavern, you must catch the Colossal Blue Dragon. This is an exotic creature that spawns randomly and stays for 15 minutes near the waterfalls. The preferred situation to catch the Colossal Blue Dragon is Clear weather, Spring or Summer season, and the Shark Head bait.
Also Read: How to Get Luminescent Oath Rod in Fisch
You can use the sundial totem to spawn the creature early. So, grab yourself a couple of Totems in Fisch before going in for the hunt. Don’t worry, it is not necessary to complete the Luminescent Cavern bestiary to unlock the Crimson door. But that is not where it stops.
Apply Crimson Mutation on Colossal Blue Dragon
After you have the Colossal Blue Dragon, you must get the Crimson mutation on it to progress. There are two ways to obtain this Fisch mutation. While you can catch Crimson mutated fish using the Scarlet Spincaster Rod, it is only obtainable from the Crimson Cavern in Fisch. So, yes, the only way to get a Crimson Colossal Blue Dragon is through the appraiser in Fisch at Moosewood.
Talk to Crimson Guard
Once you have the Crimson Colossal Blue Dragon, go to the Crimson Guard NPC beside the Crimson Cavern door. Use these coordinates to find the NPC: -1019, -336, -4332. Now talk to the NPC and submit the Crimson Colossal Blue Dragon to unlock the door to the cavern.
As you unlock the door to the Crimson Cavern in Fisch, you will find the red door gone. Equip your diving gear or the water bubble in Fisch and dive in. At the end of the tunnel, you will find the Crimson Cavern.
What are the exact keystone locations in Fisch for Luminescent Cavern access
Keystone Locations for Luminescent Cavern
Access to Luminescent Cavern in Fisch requires three specific keystones, which vary per player. Check the three pedestals at the Mysterious Crack near Sunstone Island’s Desolate Deep entrance (under the Red Buoy, right path past blue coral and Diver NPC) to identify your required ones.
All 9 Keystone Locations
There are nine possible keystones scattered across islands. Collect only the ones your pedestals demand by interacting with them at these spots:
| Keystone | Island | Coordinates | Exact Spot Description |
|---|---|---|---|
| Cliff | Castaway Cliffs | 473, 230, -2159 | Small gap beside the ledge to the second level. |
| Mushroom | Mushgrove Islands | 2666, 130, -717 | On top of the boat near Alligator abundance area. |
| Fossil | Ancient Isles | 6065, 225.5, 259.5 | Heap of woods lifted by cranes near merchant. |
| Snowflake | Snowburrow | 2788, 153.5, 2603 | Inside cave beside pine tree (unlock Snowburrow via Snowcap Cave cracks first). |
| Volcano | Roslit Volcano | -1970, 175.4, 268 | Middle stone inside the volcano. |
| Skull | Forsaken Shores | -2797.5, 209, 1544.2 | Beside pirate NPC where you fix the map. |
| Lightning | Grand Reef | -3406, 134.2, 262.2 | Small island left of Shipwright’s island. |
| Turtle | Terrapin Island | 57, 149.5, 2032 | Inside Terrapin Hideaway. |
| Sun | Sunstone Island | -935, 223, -984 | Inside Merlin’s Hut . |
Placement Steps
Equip diving gear and flippers, dive under Red Buoy, follow to warning sign > right to blue coral > right to Diver NPC and pedestals. Place matching keystones with E key (errors show mismatches). The crack opens for entry; cross Mysterious River to fish.
What rewards and rare fish are inside Luminescent Cavern
Luminescent Cavern in Fisch offers rare bioluminescent fish and progression rewards like powerful rods upon completing its bestiary. Access it via the Desolate Deep tunnel after placing the three random keystones at the Mysterious Crack pedestals.
Rare Fish List
Catch these 8-10 unique fish (including secrets) to 100% the bestiary, focusing on foggy nights in specific seasons with high-luck rods like Poseidon or No-Life Rod:
| Fish | Rarity | Best Bait | Weather/Time/Season |
|---|---|---|---|
| Bluelip Batfish | Common | Worm | Any |
| Hawaiian Bobtail Squid | Uncommon | Shrimp | Any |
| Dinoflagellates | Unusual | Weird Algae | Night, Spring |
| Blue Ribbon Eel | Rare | Flakes | Foggy Night, Autumn |
| Kitefin Shark | Legendary | Squid | Foggy Night, Winter |
| Atolla Jellyfish | Mythical | Truffle Worm | Foggy Night, Autumn |
| Electric Blue Seahorse | Mythical | Luminous Larva | Foggy Night, Spring |
| Colossal Blue Dragon | Exotic | Shark Head | Clear, Spring/Summer (use Sundial Totem for spawn) |
| Blue Sea Slug | Secret | None | Foggy Night, Winter |
| Colossal Ethereal Dragon | Secret | Truffle Worm | Any |
Key Rewards
-
Luminescent Oath Rod: Unlocked by fully completing the bestiary; excels in high-resilience catches with luck boosts.
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Bait/Enchant Access: Night Shrimp, Weird Algae, and enchants like Mystical/Steady for better rare fish rates.
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Progression Gate: Leads to Crimson Cavern gate (needs Crimson-mutated Colossal Blue Dragon).
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High-value sales from Mythical/Exotic catches for in-game currency.
Use Ethereal Prism Rod for profit farming during optimal foggy nights.
