Steal A Fish mutations are special modifiers that attach to fish as they spawn along the conveyor track, altering their cash generation or applying unique base protection. These variations range from common economic buffs like Gold to high-tier survival modifiers like Unstealable and the ultra-rare Dead mutation.
In Steal A Fish (developed by MY FISH FRIEND on Roblox), players purchase fish rolling down the central tunnel, carry them to their tycoon bases to generate passive cash per second, and defend their stashes against base raids. Because any unprotected fish can be stolen by intruders carrying weapons or slappers, securing mutated fish is essential for progressing through rebirth tiers and securing high-value income streams.
Standard Mutation Spawn Rates and Odds
Under regular server conditions, the game displays fixed percentage chances for its standard track mutations. These rolls occur automatically when a fish model emerges from the spawn chute, regardless of the base fish rarity.
The table below outlines the base mutation roll percentages observed on the in-game mutation display:
| Mutation Type | Track Spawn Chance | Primary Effect Observed in Gameplay |
|---|---|---|
| Unstealable | 7.5% | Grants a protective aura preventing other players from stealing the fish from your base slots. |
| Gold | 5.0% | Upgrades appearance to gold and boosts cash generated per second without raising purchase cost. |
| Void | 2.5% | Applies a dark cosmic finish; observed to double base cash output on standard fish variants. |
| Magma | 0.5% | Endows a glowing red lava skin with an elevated income multiplier above standard tiers. |
| Dead | 0.2% | The rarest standard track mutation, tinting the fish crimson or skeletal with top-tier output. |
Standard variants do not track as separate entries in the collection index. Inspecting the index confirms that variants such as Gold, Void, or Dead register under their core species entry rather than consuming individual index slots.
How Unstealable and Income Multipliers Function
The most strategically important standard modifier in public servers is the Unstealable mutation. Standard fish placed in your base slots are constantly exposed to intruders who can breach open gates or use gamepasses like the Invisible Cape to haul pets away. Fish carrying the Unstealable aura cannot be picked up or robbed by competitors, guaranteeing your passive earnings even if your force fields expire.
Income-focused mutations—such as Gold, Void, Magma, and Dead—apply multipliers to the fish's baseline cash production. During gameplay testing, acquiring a Void modifier on baseline fish doubled their per-second cash generation while maintaining the exact same purchase price on the track.
However, players should note the behavior of percentage-based secret fish, such as the Hungry Tongue (120% of your best pet) or Hungry Deer (150% of your best pet). Testing shows that rolling Void or Gold on certain percentage-based secret fish does not always elevate their stated fixed formula percentage. Instead, their income scales when paired with high-earning anchors like Deep-rarity bosses or multi-mutated earners placed elsewhere on your base floor.
Weather and Event-Exclusive Modifiers
Beyond the five core conveyor mutations, Steal A Fish introduces limited-time weather phenomena, update modifiers, and consumable painters that apply additional prefixes to spawns.
Blood Moon and Ancient Events
During Blood Moon weather cycles, red atmospheric lighting settles across the server, enabling fish to spawn with the Blood mutation. In-game update notices confirm that server luck boosts increase modifier spawn frequencies during these events. Similarly, Ancient events accelerate the appearance rate of Abyss-class creatures, giving players higher chances to combine rare species with atmospheric modifiers.
Rift, Aurora, and Galaxy Modifiers
Admin abuse events and server-wide weather alerts introduce high-tier environmental mutations:
- Rift Mutation: Spawned under purple lightning storms and rift skies, elevating base earnings across high-tier species such as the Abyss Seeker.
- Aurora Mutation: Introduced alongside Northern Lights weather conditions, adding distinct auras to creatures like the Aurora Whale and Aurora Secret Hungry Tongue.
- Galaxy and Infernal: Stackable modifiers observed during peak admin boost rounds, occasionally combining onto individual fish to produce multi-quadrillion per-second yields.
Fishaween Mutation Painter
During the limited-time Fishaween Halloween event, developers introduced a manual modification mechanic via the event shop. Instead of waiting for track RNG, players could spend 10,000 event pumpkins to buy the Mutation Painter consumable. Using the painter on a fish held in hand or targeted in your base directly applies the orange Fishaween modifier, enabling players to convert high-stat units like Radiated Moons or Undead Eaters into seasonal event variants.
Managing Mutated Fish During Rebirths
A common concern when collecting rare mutations is whether they survive rebirth resets. Rebirths require specific species and quantities—such as a Turtle for early ranks, Saw Sharks and Nuke Fish for mid ranks, or multiple Whales and Megalodons later on.
When you trigger a Rebirth:
- The game only consumes the specific fish demanded by that rebirth milestone.
- Unrelated mutated fish sitting on your active base slots remain completely intact.
- If an Unstealable or mutated pet fulfills the exact requirement (for instance, an Unstealable Saw Shark when a Saw Shark is required), the system consumes it to clear the milestone.
To safeguard valuable high-multiplier or Dead-mutated specimens, verify the exact rebirth shopping list before purchasing conveyor fish. If you lack open slots, sell off low-tier commons or place prize specimens inside vault slots unlocked via higher rebirth tiers and the +2 Vault Slots pass.
Frequently Asked Questions
What is the rarest track mutation in Steal A Fish?
The rarest naturally occurring conveyor mutation is the Dead mutation, which features a baseline spawn rate of 0.2% (1 in 500 fish).
Can other players steal an Unstealable fish?
No. Fish that roll the Unstealable mutation (7.5% spawn chance) or receive it from native group rewards cannot be carried or stolen by other players, even if your base gate is wide open.
Do mutations create separate entries in the Fish Index?
No. The in-game index tracks base species discovery. Variants like Gold, Void, or Magma register under the standard fish profile rather than expanding total index counts.
How do luck boosts affect mutation chances?
Purchasing server luck multipliers (ranging from 2x up to 99x) increases the arrival frequency of higher rarity tiers and elevates track modifier rates, accelerating the appearance of mutated and secret specimens.
