The Mariana's Awakening update dropped a brand-new secret zone into Roblox Fisch, and the Obsidian Trench is easily the most demanding location yet. Twelve species live here, each with specific bait, weather, time of day, and season requirements. Miss one variable and you are sitting at the bottom of the Mariana's Veil catching nothing. This guide covers every catch condition so you can hit 100% bestiary completion and unlock the Chasm-Stalker Rod.
How do you unlock the Obsidian Trench in Fisch?
The Obsidian Trench is a hidden layer inside Mariana's Veil, not somewhere you stumble into by accident. Getting there takes several steps.
Start by speaking to Vaelor in Roslit Bay to kick off the Mariana's Awakening questline. He sends you to investigate glowing mineral veins across all five Mariana's Veil layers. Each layer has one of Vaelor's descendants guarding it: look for them across the Volcanic Vents, Challenger's Deep, Abyssal Zenith, Calm Zone, and Veil of the Forsaken. Complete the specialized mutation quest for each descendant to collect the five Gauntlets associated with the NPCs Ignis, Glacius, Tenebris, Luminis, and Resonus.
Once you have all five Gauntlets, head to the Obsidian Pocket area. Solve the active wall riddle at the Crevice Wall, ignite all layer gems, and the underground door opens. That takes you straight into the Obsidian Trench.
Fisch Guide: All 12 Fish in Obsidian Trench
All 12 Obsidian Trench fish
Every fish in the Obsidian Trench has a fixed set of catch conditions. The table below has everything you need. Sort your sessions by season first, then plan around weather and time of day to stack multiple catches per visit.
| 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 |
| Skolopendra (Exotic) | Kraken Tentacle | Rain or Foggy | Any | Autumn, Winter |
| Veiled Charybdis (Apex) | Meteor or Sea Beetle | Any | Night | Any |
Planning your sessions by season
Summer is the busiest season for this bestiary. The Pumice Puffer, Cinder-Crust Gar, Magma-Glass Marlin, Shatter-Tooth Shark, Obsidian Gaveltooth, Shatterjaw Shark, and Basalt Behemoth all appear during Summer. If you are grinding in Summer, bring Shrimp, Minnow, Squid, Fish Head, and Magnet to cover every possible catch in one session depending on the weather.
Autumn covers the Scoria Scorpionfish, Ash-cloud Angelfish, Obsidian Gaveltooth, Tectonic Toadfish, Skolopendra, and Basalt Behemoth. The two Autumn-exclusive daytime fish (Scoria Scorpionfish and Ash-cloud Angelfish) both need Clear weather, so time your Autumn visits around clear skies before switching to Foggy conditions for the Tectonic Toadfish at night.
Winter is the lightest season here. Only the Tectonic Toadfish, Shatterjaw Shark, Skolopendra, and Basalt Behemoth are catchable. That said, Winter is a solid time to target the Skolopendra since it accepts both Rain and Foggy weather with no time restriction.
Fisch Guide: All 12 Fish in Obsidian Trench
The two hardest catches explained
The Skolopendra is listed as Exotic rarity and requires Kraken Tentacle bait, which is not a standard shop item. Make sure you have this bait stocked before entering the Trench in Autumn or Winter. It has no time restriction, so at least you can fish for it around the clock once conditions are right.
The Veiled Charybdis is the Apex of the Obsidian Trench and accepts either Meteor or Sea Beetle bait. It only appears at Night but has no season or weather requirement, making it one of the more flexible catches despite its rarity. Night sessions with either bait type are your best window.
Why should you complete the Obsidian Trench bestiary?
The primary reward is access to the Chasm-Stalker Rod. Completing the full bestiary is a hard requirement to purchase it, on top of its C$5,000,000 price tag. The rod comes with a new mutation, strong passive bonuses, and a unique streak system that no other rod in the game uses. For players looking to push their fishing builds further, the Chasm-Stalker Rod is the main reason to grind through all 12 entries.
Defeating the Skolopendra boss is also tied to this progression, so catching the Exotic-rarity Skolopendra fish is not just a bestiary checkbox but part of unlocking the full Obsidian Trench experience.
For the full picture on Fisch companions that complement your fishing runs, the Roblox Fisch companion guide covers all 10 companions with GPS coordinates and required baits. Check the rest of our Roblox guides for more Fisch bestiary coverage across every location in the game.
