Roll a Fisherman Fish Mutations: Costs, Outcomes, and Income

Quick answer

You mutate a fish in Roll a Fisherman at the Mutation Machine while holding the fish you want changed. Each attempt costs 100 Gold — 50 Gold if your fisherman has the 'Mutations cost half as much gold' perk — and rolls a random mutation onto that fish. A mutation gives the fish a rare trait and raises the Cash it earns, but the outcome is random, and the on-screen odds have been seen to change between attempts.

• Mutating runs on Gold, not Cash: Cash buys fishermen and meets rebirth requirements, while Gold pays for special upgrades and mutations.
• Confirmed mutation names: Shiny, Pixel, Molten, Glitched, Plasma, and Galaxy.
• Without a fish in hand, the machine rejects the attempt with 'Hold a fish first.'
• Fish can also be caught already mutated, without ever using the machine.
• Exact odds per mutation and fixed income multipliers aren't pinned down anywhere in the game — treat on-screen odds as subject to change.

Where and how to mutate a fish

The mutation entry point is the Mutation Machine, a Gold-cost station that recorded gameplay shows sitting next to the Gold upgrade area where Fishing Speed, Catch Luck, Mutation Luck, and Roll Luck are sold. To use it, be holding the fish you want to change — one attempt was rejected with the prompt 'Hold a fish first' before a mutation finally went through — then pay for a roll, which applies a mutation outcome to that fish. A mutate action is also offered directly on freshly caught fish: one recorded sawfish catch prompted 'Do I mutate this?' on the spot.

What a mutation costs

Observed play shows the Mutation Machine charging 100 Gold per mutation. A fisherman with the 'Mutations cost half as much gold' perk — seen on Coral Zoey — drops the charge to 50 Gold. Watch out for a quirk here: the displayed price does not reflect the discount until the mutation is actually attempted, as one player discovered mid-roll ('It's 50 cuz it's half price. Just didn't tell me.'). These costs come from gameplay sessions, so recheck them after any mutation-related update.

Mutation outcomes and traits

Each roll lands on one of the named outcomes below:

Comparison

Comparison

Mutation	Use or observation
Shiny	The most basic outcome — gameplay calls it 'literally the first mutation.' Useful for early mutation and collection progress; keep strong examples and sell weak extras. A shiny rare crab earned 21 per second.
Molten	A mutation-based income increase. Compare earnings before replacing a Molten fish.
Glitched	Rare mutation with strong earning potential; prioritize attempts on valuable fish. Observed at 1% displayed odds.
Plasma	An event or mutation-focused target; keep eligible fish during mutation surges. A Koi Fisher's 'Mutation Surge' perk makes Plasma twice as likely.
Pixel	Seen applied to high-value catches (Pixel Beluga, Pixel Orca); the player calls it 'very good.'
Galaxy	Observed at 6% displayed odds on a sawfish earning 31k per second.

How mutation odds work when rolling

Every machine attempt rolls against per-outcome chances shown in the UI — but those numbers are not fixed. Glitched displayed at 1% in one session ('the glitch is 1%'), later at 8% ('wasn't that like 1%?'), and then at 3.5% and 1.5% on a later fish, with the player noting the game 'just switched the chances.' Fisherman perks can shift odds too: the rare Koi Fisher's 'Mutation Surge' perk makes Plasma twice as likely. The main risk of paying per roll is landing a cheaper outcome while chasing a rare one — the same player repeatedly paid hoping for Glitched and received Pixel and Molten instead. Check the current odds on screen after any mutation-related update rather than trusting older numbers.

Fish can come pre-mutated

Mutations are not exclusive to the machine. Fish caught normally can already carry a mutation applied — one player caught mutated common fish (auto-sold before even noticing) and unlocked the 'Prismatic' title, whose requirement reads 'Catch a fish of every mutation,' a collection goal spanning all mutation types. Natural mutations include Shiny, the first/basic mutation; a shiny rare crab earned 21 per second.

How mutations change fish income

Mutated fish earn more Cash per second. Observed examples: a Galaxy sawfish making 31k every second, a Glitched worm 'now making a lot of money,' and a Glitched monkfish jumping from about 140k a second to roughly 840k a second after further boosts. Mutations double as collection goals on top of the income. What the game doesn't spell out is a fixed multiplier per mutation type, so the only reliable comparison is the before-and-after earnings on your own fish.

Mutation Luck and its limits

Mutation Luck is one of the special stats bought with Gold, listed alongside Fishing Speed, Catch Luck, and Roll Luck as upgrades that speed up progress, and it appears in the Gold upgrade area next to the machine. Its exact effect on mutation rolls hasn't been documented — the confirmed part is simply that it exists as a purchasable Gold stat, so treat how much it helps as unknown until you can judge your own roll results.

Which fish are worth mutating

Spend mutation attempts on fish with strong base value — improving a valuable catch gives far more benefit than mutating the weakest fish on the dock — and only when the cost fits your current Gold supply. Recorded play follows exactly this pattern: the player saved mutations for a mythic Beluga ('6.35k base value. Yeah, we're mutating you, bud') instead of wasting rolls on trash fish. Keep in mind that Gold is limited and shared with stat upgrades; it comes from special wheel results and from selling certain high-tier mythic-plus fish. One planning caveat: an in-game tip says to 'obtain gold by indexing fish or selling mythic plus ones,' but the same recorded player indexed many fish without receiving Gold, while selling mythics did pay out (4 Gold per mythic). Check what indexing actually pays on your account before counting on it to fund mutations.