Find All Fish Ruins Keys in Abyss (March 2026) Full Guide

If you’ve been grinding through Abyss lately, you’ve probably stumbled upon the Fish Ruins. Or maybe you’ve been swimming in circles, completely lost, wondering where the heck the entrance is. Trust me, I’ve been there. The Fish Ruins is one of those late-game areas that feels like a blend of Lovecraftian horror and a classic Metroidvania puzzle box.

It’s not just a pretty face, though. This area is gated by a series of locked doors that require specific keys to open. Inside? Some of the best loot in the game, lore fragments that explain the origin of the abyssal corruption, and a boss fight that will test your dodge-rolling skills. In this guide, I’m going to walk you through every single key location in the Fish Ruins so you can stop searching and start looting.

Why I Enjoy Exploring the Fish Ruins?

I’ll be honest—when I first entered the Fish Ruins, I was frustrated. The lighting was dim, the enemies were spongy, and I couldn’t find the first key to save my life. But once I slowed down and actually looked at the environment design, I realized how brilliant it is.

The atmosphere is thick with tension. The sound design—echoing drips, distant whale calls, and the unsettling silence of the deep—makes every step feel significant. I love how the game rewards observation. The keys aren’t just sitting on a pedestal; you have to solve environmental riddles or defeat mini-bosses to get them. It’s that “aha!” moment when the door finally creaks open that keeps me coming back.

All Fish Ruins Key Locations (Walkthrough Guide)

Let’s get to the meat of it. There are three main keys you need to unlock the inner sanctum of the Fish Ruins: the Rusted Coral Key, the Obsidian Fish Key, and the Sapphire Heart Key. Missing even one means you’re locked out of the final chamber.

Here is my step-by-step breakdown for finding each one.

1. Rusted Coral Key

This is usually the first one players miss because it’s easy to overlook.

• Location: The Sunken Gallery.
• How to get it:
  1. From the first bonfire in the ruins, head left instead of right (the “intended” path).
  2. You’ll see a crumbling bridge. Don’t cross it. Drop down into the water below.
  3. There is a hidden alcove behind a breakable wall covered in red kelp. You need a heavy weapon to break it.
  4. Inside, you’ll face a Drowned Gladiator. He hits hard, but he’s slow. Kite him around the pillars.
  5. Defeat him, and he drops the Rusted Coral Key.

Pro Tip: Don’t ignore the breakable walls! If you see a faint crack with light peeking through, smash it. I missed this for an hour because I was trying to find a switch.

2. Obsidian Fish Key

This one involves a bit of platforming, which can be tricky with Abyss’s floaty underwater physics.

• Location: The Apex Pillar.
• How to get it:
  1. Fast travel to the “Statue of the Mother” checkpoint.
  2. Look up. You’ll see a series of floating platforms.
  3. You need to time your jumps with the water currents. The currents push you left, then right, every 3 seconds.
  4. Climb to the very top of the room. You’ll see a fish skeleton made of obsidian hanging from the ceiling.
  5. Interact with the skeleton to pull the Obsidian Fish Key from its mouth.

I died twice here because I got greedy with the jumps. Take your time. The key isn’t going anywhere.

3. Sapphire Heart Key

This is the final key and arguably the hardest to secure.

• Location: The Abyssal Maw.
• How to get it:
  1. You need to have defeated the Abyssal Maw Mini-Boss (a giant crab variant).
  2. Once the boss is down, the water level in the room will drain.
  3. Drop down the central drain pipe.
  4. You’ll enter a room with a puzzle. There are three statues holding tridents. You must rotate them so they all point toward the center of the room.
  5. A chest spawns in the center containing the Sapphire Heart Key.

Common Bug Alert: Sometimes the chest doesn’t spawn if you kill the boss too quickly (speedrunners beware). If this happens, restart the area from the checkpoint. It’s a known issue that the devs are patching soon.

Fish Ruins Key Locations Overview (March 2026)

Here is a quick reference table I put together to save you some time:

Tips & Tricks for the Fish Ruins

Navigating the ruins isn’t just about finding keys; it’s about surviving. Here are a few things I wish I knew before I started:

1. Bring a Torch: Some areas are pitch black. While you can use a glow-stick, a torch keeps one hand free for your weapon and lights a wider radius. It helps spot those sneaky ambush enemies.
2. Poison Resistance is Mandatory: The enemies here inflict “Deep Rot,” a poison variant that drains health rapidly. Stack resistance gear or bring plenty of antidotes.
3. Check the Walls: I mentioned this earlier, but it’s worth repeating. The level design in the Fish Ruins loves false walls. If a wall looks slightly different or has a glowing rune faintly visible, hit it.
4. Enemy Weaknesses: The enemies here are weak to Lightning and Fire. If you’re running a pure Frost build, you’re going to have a bad time. Consider swapping your build at the nearest mirror.

Latest Updates & Patches

The devs have been active recently. The latest patch (v1.03) actually changed the location of the Obsidian Fish Key slightly—it used to be in the Maw, but they moved it to the Apex Pillar to fix a sequence break. Make sure your game is updated, or your guide might be outdated!

Also, keep an eye on the event tab. Rumor has it that next month’s “Festival of Lights” event will add a secret fourth key to the Fish Ruins that unlocks a cosmetic armor set. I’ll update this guide as soon as I get my hands on it.

Frequently Asked Questions

Can I enter the Fish Ruins early?

Technically, yes. You can glitch through the door using a specific dodge-roll technique, but the enemies inside are scaled for late-game levels. I tried this at level 10 and got one-shot. I recommend waiting until you finish the main story Act 3.

What happens if I lose a key?

Keys in Abyss are not consumable items. Once you pick them up, they stay in your Key Items inventory. If you drop a key (which you can’t normally do), it usually bugs the game. Just keep them!

Is there a map for the Fish Ruins?

Yes! You can buy the “Ruins Map Fragment” from the merchant at the entrance of the zone for 500 gold. It reveals the location of the Rusted Coral Key but not the others. It’s worth the investment if you hate getting lost.

What is the reward for opening the final door?

Inside the final sanctum, you’ll find the Trident of the Deep, a legendary weapon that scales with Strength and deals massive poison damage. It’s currently one of the best weapons for tank builds.

Final Thoughts

Getting all the keys in the Fish Ruins is a rite of passage in Abyss. It tests your exploration skills, your combat reflexes, and your patience. But standing in that final treasure room, holding the Trident of the Deep, makes all the frustration worth it. I hope this guide helped you find that one missing key you were looking for.

If you found this helpful, let me know in the comments or check out my other guides on boundbyflame.com. Good luck down there—I’ll see you in the depths