If you’re looking for one of the most profitable mutations in Fisch, the Mastered mutation should be high on your list. Not only does it completely transform the appearance of a fish, but it also dramatically increases its selling price, making it one of the best mutations for players who want to farm money efficiently.
The catch is that you can’t obtain it with just any fishing rod. You’ll need a specific rod and, ideally, perfect catches to make the most of its unique passive.
Here’s everything you need to know.
How to Get the Mastered Mutation in Fisch (Ruinous Oath Guide)
The Mastered mutation is a special fish mutation that significantly increases the value of any fish caught with it.
Mastered Mutation Bonus
- Sell Value Multiplier: 8×
An eight-times value multiplier makes this one of the strongest money-making mutations currently available. Catching rare fish with the Mastered mutation can result in extremely valuable sales, especially when combined with other money-boosting mechanics.
How to Recognise a Mastered Fish
Mastered fish have a unique appearance that makes them easy to identify in your inventory.
When a fish receives this mutation, it gains:
- A glowing sandy-textured body.
- Colours that shift between red and blue.
- Matching coloured particles surrounding the fish.
- A distinct animated visual effect.
Because of these effects, Mastered fish stand out immediately from normal catches.
How to Get the Mastered Mutation
The Mastered mutation is tied directly to a specific fishing rod.
To obtain it, you’ll need the Ruinous Oath Rod.
Unlike most mutations that rely entirely on luck, the Ruinous Oath Rod has its own passive ability that gives players a reliable way to obtain Mastered fish.
Ruinous Oath Rod Passive
The Ruinous Oath Rod has two different chances of applying the Mastered mutation depending on how well you complete the fishing minigame.
Perfect Catch
If you land a Perfect Catch, the rod guarantees the mutation.
- 100% chance to apply Mastered
That means every perfect catch made with the Ruinous Oath Rod will become a Mastered fish.
Normal Catch
Even if you don’t manage a Perfect Catch, you still have a chance.
- 25% chance to receive the Mastered mutation.
While not guaranteed, this still makes the Ruinous Oath one of the most reliable rods for farming valuable mutations.
How to Get the Ruinous Oath Rod
Before you can start farming Mastered fish, you’ll first need to unlock the rod itself.
Travel to the Crimson Cavern.
The Ruinous Oath Rod is obtained from this area, making Crimson Cavern an essential destination for anyone interested in high-value mutation farming.
Once you’ve unlocked the rod, simply equip it before heading out to fish.
Why Perfect Catches Matter
The biggest advantage of the Ruinous Oath Rod is its guaranteed passive.
Since Perfect Catches always trigger the Mastered mutation, improving your timing is much more valuable than relying on luck.
If you consistently land Perfect Catches, every fish you catch becomes significantly more profitable.
Spending a little time practising the fishing minigame can easily pay for itself through the increased sell value.
Best Uses for the Mastered Mutation
The Mastered mutation is particularly useful when you’re:
- Farming money.
- Catching high-value legendary fish.
- Hunting rare species.
- Building a valuable collection.
- Selling large batches of fish.
Because the multiplier affects the final selling price, applying it to naturally valuable fish leads to the biggest profits.
The Mastered mutation is one of the best mutations in Fisch for players who want to maximise their earnings. By unlocking the Ruinous Oath Rod in Crimson Cavern, you gain access to a unique passive that guarantees the Mastered mutation on every Perfect Catch and still provides a 25% chance on regular catches.
With its impressive 8× sell value multiplier, distinctive glowing appearance, and reliable activation through skilled fishing, the Mastered mutation is an excellent choice for both collectors and players looking to build up their in-game wealth quickly.