So the new Luminescent Cavern Update (v1.50, Sept 20, 2025) dropped and if you haven’t been in yet, you’re missing out. The update added the Scarlet Spincaster Rod and a new type of mutation called Crimson, which basically makes your fish glow blood red and sell for way more than normal.
Here’s how you can get the Scarlet Spincaster Rod and Crimson mutation in Roblox Fisch.
How To Get Scarlet Spincaster Rod in Roblox Fisch
First off, the rod isn’t just handed to you. You need to get into the Luminescent Cavern, which is like a hidden sub-zone off the Desolate Deep. If you’re not at least Sea 2 and around level 50, don’t even bother. The currents, enemies, and depth will eat you alive.
How to actually get there:
- Go to the Desolate Deep. Upgrade your boat first or you’ll regret it.
- Swim down until you see glowing plants around cave entrances. That’s your ticket inside. It’s really obvious once you know what to look for, but I swam in circles for a while like an idiot before spotting the glowing doorway.
Inside the cavern, there’s this merchant NPC near some giant glowing crystals. That’s where you buy the rod. It costs somewhere between 50k and 75k C$, which sounds brutal, but honestly it’s not that bad if you farm Deep fish with Glow Worms for a bit.
The rod’s stats are kind of wild:
- Luck boost of about +20–30%
- Mutation chance for Crimson +15%
- Lower resilience -10%
Basically it’s a glass cannon fishing rod. Perfect for farming mutations, but if you hook a monster, expect a fight. I had one snap my line while I was half paying attention. Lesson learned.
Farming Crimson Mutations
So what’s the point of the rod? Crimson Mutations. When you pull one, your fish turns this deep glowing red and the sell value jumps by six times. Yes, six. My first one sold for enough to make me stare at the screen for a solid minute.
Here’s how you actually get them:
- Equip the Scarlet Spincaster Rod. Don’t even bother without it. Base chance without is like 0.5%. With it, you’re pushing 10% or more if you do everything right.
- Go into the Crimson Cavern. This is a red glowing cave inside the Luminescent Cavern. You’ll know it when you see it. Weak currents push you around but nothing too deadly.
- Use Bloodworms or Deep Lures. You can fish with anything, but these boost your odds of pulling rare fish, which makes the Crimson Mutation more likely.
- Watch for Event Tides. The game announces them in chat. Wait a few minutes and fish during those. Feels like the odds spike big time.
- Target big fish. If you can hook something like a Colossal Blue Dragon or even Moby Dick, pray for a Crimson roll. Those are insane money makers.
There’s also this trick with the Appraiser NPC on Ancient Isle. You can pay 25% of the fish’s value to gamble for a 25% shot at forcing the Crimson mutation. I was skeptical but it actually works often enough that I keep using it. It’s kind of like paying to reroll a loot box.
Stack bonuses if you want to sweat it:
- Enchant your rod with Mutated or Mutation Surge.
- Fish during admin events like Supersized or Mayhem. Crimson odds shoot way up then.
