Crimson Cavern is a late-game sublocation with its own bestiary and unique gear rewards. Access requires a Crimson mutation on a Colossal Blue Dragon to open the red gate in Luminescent Cavern, followed by an underwater tunnel to the cavern proper. For location specifics, entry steps, and event rules, see the official Crimson Cavern page once at fischipedia.org/wiki/Crimson_Cavern.

Unlock Crimson Cavern access (requirements)

Crimson Cavern is reached from Luminescent Cavern after you complete the Crimson Guard requirement: provide a Colossal Blue Dragon with the Crimson mutation. Appraising a Colossal Blue Dragon repeatedly is the recommended way to roll this mutation. After opening the red gate, use diving gear to safely traverse the underwater tunnel to the cavern.

The official wiki lists the area GPS as -1035, -360, -4800 and confirms the presence of crab cage fishing inside the cavern.

Crimson Cavern bestiary — fish and conditions

The official bestiary for Crimson Cavern tracks 8 unique catches. Community guides sometimes include an additional Legendary eel; use the table below to focus on the 8 entries that count toward the Cavern’s page completion.

Fish Bait Weather Time Season Notes
Red Spotted Blenny Worm. Clear. Day. Spring. Common day catch; appears via crab cages.
Sea Raven Worm. None. Day. Winter. Community reports favor Rain, but official lists no weather requirement.
Red Crabsquid None. Clear. Day. Summer. Higher odds in Crimson crab cages.
Viperfish Minnow. None. Night. Winter. Community guides note strong results in Rain and darker water.
Red Fangtooth Flakes. None. Night. Autumn. No weather requirement per official; some players target Rain regardless.
Vampire Squid Truffle Worm. Foggy. Night. Autumn. Mythic; higher resilience.
Lithodes Megacantha Weird Algae. Foggy. Night. Spring. Exotic; can also appear via crab cages.
Colossal Ancient Dragon Shark Head. Clear. None. Spring, Summer. Exotic; only during Hunt event (see Method 2 below).

Finish the Crimson Cavern bestiary efficiently

Step 1: Stock the exact baits you’ll need. Bring Worms, Flakes, Minnow, Truffle Worm, Weird Algae, and a Shark Head. Having the full set prevents dead time when the right weather and season line up for a specific catch.

Step 2: Optimize your rod for high-resilience targets. Apply Resilient and Quality to steady hook movement against tougher fish. If you have Exalted Relics, roll for Mystical to improve progress and luck, and consider Steady or Flashline to counter negative progress speeds common in cavern fish.

Step 3: Fish by condition windows, not by species. Rotate through day/night and seasons to clear clusters together (e.g., daytime Clear Spring targets Blenny; nighttime Foggy Autumn targets Vampire Squid). This reduces idle time waiting on a single missing entry.

Step 4: Use crab cages for crustacean entries. Place and check cages during Clear Summer daytime for Red Crabsquid, and keep a few cages running in Foggy Spring nights to roll for Lithodes Megacantha while you rod-fish nearby.

Step 5: Prioritize rare windows with higher failure cost. Queue Foggy nights first for Vampire Squid and Lithodes Megacantha. Run daytime clears between fog cycles to pick up Blenny/Crabsquid without wasting fog uptime.

Step 6: Keep a “rain route” ready. While official entries don’t require Rain for Sea Raven, Viperfish, or Red Fangtooth, community routes often use Rain for these three at once. If Rain starts, pivot to those targets to compress your schedule.

Catch the Colossal Ancient Dragon (Hunt events)

Step 1: Watch for the Hunt event callout. The Colossal Ancient Dragon only spawns during a random Hunt event. The active pool shows yellow lightning particles with dark fog and appears as a red pool on the Fish Radar.

Step 2: Equip Shark Head bait before engaging. Seasons must be Spring or Summer, with Clear weather; time of day does not matter. Pre-loading the bait prevents losing the pool to despawn while you swap gear.

Step 3: Use Sundial Totems if available. These can trigger the Hunt, reducing wait time. Move quickly to the marked pool, cast immediately, and maintain tension through the fight—this is an Exotic catch with very high resilience.

Gear and shop rewards in Crimson Cavern

Completing the Cavern bestiary unlocks major gear paths sold inside the area. Requirements and pricing are set in C$ (in-game currency):

Item Cost Requirement
Ruinous Oath (rod). C$ 30,000,000. Level 1000; 100% Shiny + Sparkling Crimson Cavern bestiary.
Wicked Fang Rod. C$ 3,700,000. Purchasable only during the Eclipse event.
Scarlet Spincaster Rod. C$ 200,000. No special requirement noted.

Notes on discrepancies you may see in community guides

Some guides list a ninth fish (a Legendary eel) within Crimson Cavern conditions. The official bestiary page counts 8 entries for Crimson Cavern completion, and the table above reflects those 8. Additionally, while several community routes target Rain for Sea Raven, Viperfish, and Red Fangtooth, the official entries do not require Rain; treat Rain-based targeting as an optional efficiency route rather than a hard requirement.

Plan your runs around foggy nights and the Hunt window, keep all baits on-hand, and you’ll finish the page without wasted cycles.