The Forgotten mutation is one of the standard mutations in Fisch, and it raises the sell value of any fish it lands on by 2x. Unlike many mutations that can show up by pure luck across the map, Forgotten is tied almost entirely to a single rod, which makes farming it far more predictable once you have the right gear equipped.
Quick answer: Equip Thalassar’s Ruin and keep fishing. It applies the Forgotten mutation with a 90% chance every 25 seconds.
What the Forgotten mutation does
Forgotten is a value mutation. When a fish carries it, the catch sells for 2x its base price. It sits in the same tier as several other 2x mutations in the game, so its main appeal is the steady, repeatable way you can apply it rather than a uniquely high multiplier.
| Property | Detail |
|---|---|
| Mutation type | Standard |
| Value multiplier | 2x |
| Main source | Thalassar’s Ruin rod |
| Trigger rate | 90% every 25 seconds |
How to get the Forgotten mutation with Thalassar’s Ruin
The reliable route runs through one rod. Thalassar’s Ruin carries a built-in chance to stamp the Forgotten mutation onto your catches on a fixed timer, so the method is simply equipping it and fishing actively.
How to confirm a fish has the Forgotten mutation
A successful catch shows the Forgotten mutation label on the fish, and its sell value reflects the 2x increase compared to the same fish without any mutation. If the multiplier and tag are both present, the roll worked.
Note: The 90% rate is not a guarantee. A catch can come up without Forgotten even with Thalassar’s Ruin equipped, since the chance is rolled on each 25-second interval. If you go several cycles without it, that is expected variance, not a broken trigger.
For consistent results, the priorities are straightforward. Have Thalassar’s Ruin equipped, keep fishing through full timer windows, and check the mutation tag on each catch to track how many Forgotten fish you have pulled.
