The Acidgrinder is a late-game fishing rod in Fisch, added during the Venue Takeover event. It fishes safely in Lava, Noxious Fluid, and Brine thanks to a 200 Durability rating, and its Charge Meter lets you push Progress Speed higher the longer you hold your input. Getting it means finishing a three-part quest chain handed out by Axel, and each step locks behind a specific mutation and a specific fish.
Quick answer: Reach the Underground Music Venue, then complete Axel’s three quests in order — catch a Tainted Brine Phantom, catch a Brined Brine Sovereign (this rewards the restricted Acidgrinder), then catch an Acidic Caustic Starwyrm using that restricted rod. Returning the last fish removes the restriction and unlocks the full Acidgrinder.
Rods and items you need before starting
Most of the grind happens at the Brine Pool past Desolate Deep, and each quest step requires a tool you cannot skip. Line these up first so you are not backtracking mid-questline.
| Requirement | Why you need it |
|---|---|
| Bloomspire: Twisted Toxins rod | Only rod that applies the Tainted mutation (40% chance). Buy the Bloomspire rod at the Living Garden, then use a Toxic Lotus on it in the Toxic Grove. |
| Brine-Infused Rod | Applies the Brined mutation. Sold at the Brine Pool for 75,000 coins, with a 50% chance to proc the mutation. |
| Reinforced Rod (or better) | Survives fishing in brine liquid without snapping your line while you travel to the Brine Pool. |
| Chaotic Enchant Relic | Placed on the Crystal Cove pedestal to open the trapdoor into the Underground Music Venue. |
Tip: Getting the Toxic Lotus is its own side task. Plant a Rotten Seed inside the Living Garden and wait for it to grow into a Toxic Lotus before you can upgrade the Bloomspire rod.
Reach the Underground Music Venue and find Axel
Complete Axel’s three quests
Quest 1: Catch a Tainted Brine Phantom
The Brine Phantom spawns in the Brine Pool. Fish it with the Bloomspire: Twisted Toxins rod, which has a 40% chance to apply the Tainted mutation. The mutation does not proc on every catch, so expect to keep casting until a Tainted Brine Phantom appears, then return it to Axel. This is the grindiest step of the chain.
Quest 2: Catch a Brined Brine Sovereign
The Brine Sovereign only spawns at the Brine Pool during a Brine Storm. The storm has a 1% chance to trigger during Rain and lasts about 2 minutes once active, and it applies a 50% Lure Speed debuff while running. Bring a high Lure Speed rod to counter that, and use the Brine-Infused Rod to apply the Brined mutation. Server hopping into a Rain server speeds this up considerably. Returning the Brined Brine Sovereign rewards the restricted version of the Acidgrinder.
Quest 3: Catch an Acidic Caustic Starwyrm
The Caustic Starwyrm also appears at the Brine Pool during a Brine Storm. You must catch the Acidic version using the restricted Acidgrinder that Axel just handed you. The Acidgrinder itself carries a 40% chance to apply the Acidic mutation, so keep fishing until it procs. Return the Acidic Caustic Starwyrm to Axel to finish the chain.
How to confirm the Acidgrinder is unlocked
Once you return the Acidic Caustic Starwyrm, the Restricted tag is removed from the rod and Axel awards the full, unrestricted Acidgrinder. At that point you have access to all of its passives, including the full Charge Meter range. If the rod still shows as restricted, you have completed the catch but not returned the fish to Axel — hand it in to finalize the reward.
Acidgrinder stats and passive
| Stat | Value |
|---|---|
| Lure Speed | 83% |
| Luck | 185% |
| Control | -0.02 |
| Resilience | 30% |
| Max Kg | Infinite |
| Durability | 200 (Lava, Noxious Fluid, Brine) |
| Progress Speed | Fluctuates with Charge |
The passive works in two parts. First, every catch has a 40% chance to apply the Acidic mutation (7.3x value). Second, the Charge Meter builds while you hold an input and drains when you let go. Charge grants a baseline 25% Progress Speed and 25% Forced Progress Speed, both of which scale up as the meter fills, adding up to roughly +50% at full charge. That makes short work of Progress-Locked fish once you learn the timing.
Note: The one weak point is Control at -0.02, which shrinks your reeling bar. Applying a Control-boosting enchantment fixes this. You can enchant rods at the Keeper’s Altar, reached by paying 400C$ to Cole at the Statue of Sovereignty.
The Venue Takeover NPCs are described as available for an unknown limited time, so the Acidgrinder is worth chasing sooner rather than later if you want it in your rotation. Its high durability, wide stat spread, and Charge Meter make it a dependable all-purpose rod for hazardous fishing spots once the questline is behind you.
