The Obsidian Trench sits deep inside Mariana’s Veil and holds 12 exclusive fish, each with its own bait, weather, time, and season conditions. Ten of them are standard catches you can farm right away. The final two, Veiled Charybdis and Skolopendra, only appear through a chained boss trigger, which is what makes full completion a genuine grind.
Quick answer: Catch the 10 regular trench fish with their listed bait and conditions, reel in Veiled Charybdis 4–6 times at night to turn the crystals red, then catch the awakened Skolopendra with Kraken Tentacle to hit 100%.
Unlock the Obsidian Trench first
You cannot fish the trench until you finish the Mariana’s Awakening progression. The full path runs through five layer quests, a wall riddle, and the Abyss Gate.
- Speak to Vaelor in Roslit Bay to start investigating the glowing mineral veins.
- Complete the mutation quests for his five descendants: Ignis (Volcanic Vents), Glacius (Challenger’s Deep), Tenebris (Abyssal Zenith), Luminis (Calm Zone), and Resonus (Veil of the Forsaken).
- Reach the Crevice Wall in the deeper abyss and solve its riddle.
- Ignite all five layer gems to open the Abyss Gate and enter the trench.
Manage Trench Suppression while fishing
The moment you enter, an environmental debuff called Trench Suppression starts reducing your effectiveness, and it builds up the longer you stay. To clear it, interact with the glowing white crystals scattered around the trench, which temporarily purge your suppression level.
Before settling into a fishing spot, locate several white crystals nearby so you can reset suppression without hunting for one mid-session.
The 10 regular Obsidian Trench fish
These ten register through normal fishing. Match the bait and conditions below to raise your encounter chance, then keep casting until only the two special silhouettes remain on the page.
| Fish (Rarity) | Bait | Weather | Time & Season |
|---|---|---|---|
| Pumice Puffer (Common) | Shrimp | Clear | Day, Summer |
| Scoria Scorpionfish (Common) | Shrimp | Clear | Day, Autumn |
| Ash-cloud Angelfish (Uncommon) | Seaweed | Clear | Day, Autumn |
| Obsidian Gaveltooth (Unusual) | Fish Head | Clear | Night; Summer, Autumn |
| Cinder-Crust Gar (Rare) | Minnow | Rain | Day, Summer |
| Tectonic Toadfish (Rare) | Worm | Foggy | Night; Autumn, Winter |
| Basalt Behemoth (Legendary) | Magnet | Rain | Night; all seasons |
| Magma-Glass Marlin (Legendary) | Squid | Clear | Day, Summer |
| Shatter-Tooth Shark (Legendary) | Fish Head | Foggy | Night, Summer |
| Shatterjaw Shark (Mythical) | Fish Head | Rain | Night; Summer, Winter |
Faster catches matter more than anything here. A rod with a passive that pulls extra fish alongside your main catch, such as the Toxinburst Rod, fills these entries quicker, and the harpoon helps with heavier targets like the Tectonic Toadfish.
Catch Veiled Charybdis (Apex)
Veiled Charybdis is the first special entry, and it does not spawn in the open trench. Fish for it in the rivers inside the Obsidian Trench at night, using Meteor or Sea Beetle (Stag Beetle) bait. Hooking it starts a high-stakes reeling minigame.
Whirlpools appear during the fight and can strip your rod control. React the instant one shows rather than forcing the fishing bar, or you will lose the catch.
Awaken and catch Skolopendra (Exotic)
Skolopendra never appears on a normal cast. You have to awaken it by catching Veiled Charybdis repeatedly. This is the trigger that turns 10/12 into a completed page.
Landing Skolopendra fills the final entry. Do not try to reach it before finishing the Charybdis catches, since those are what wake it up.
Confirm 100% and claim the rewards
Once all 12 silhouettes are filled, the bestiary displays the completion confirmation and plays its first-open jingle for the page. You receive the Obsidian Chunk Bobber as the completion reward.
Completing the trench progression and defeating Skolopendra grants access to the Chasm-Stalker Rod through the area’s crystal interaction. It costs C$5,000,000 and introduces a new mutation, powerful passive effects, and a rod-exclusive streak system, so completing the full bestiary provides the route to one of the game’s newest rods.
