Mutations in Be a Fish Bait change how a fish looks and, more importantly, how much money it earns per second in your aquarium. There are eight of them as of the Delulu Update, each attached to a fixed earning multiplier, and stacking the right ones is the fastest way to turn a plain catch into a top earner.
Quick answer: Radioactive is the strongest single mutation at 8x. To hit the biggest possible payout, land a fish carrying Radioactive plus both stackable specials, giving you the Radioactive x Delulu x Champion combo.
All Be a Fish Bait mutation multipliers
Every mutation applies a flat multiplier to a fish’s earning rate. Rarer mutations carry bigger multipliers and appear far less often, so the higher the payout, the lower the odds of it landing on any given cast.
| Mutation | Earning multiplier |
|---|---|
| Gold | 1.5x |
| Diamond | 2x |
| Delulu | 2x |
| Champion | 3x |
| Plasma | 4x |
| Glitched | 5x |
| Molten | 6x |
| Radioactive | 8x |
Note: The developers add new mutations over time, so this list reflects the current Delulu Update lineup.
How mutated fish are rolled
Catching a mutated fish is completely RNG-based. Every time you cast the line, there is a chance the fish comes back with a random mutation attached. You cannot force a specific one, but several tools tilt the odds in your favor.
- Equip Auras that raise Mutation Luck. The Yinyang and Voidspore auras both boost mutation luck and noticeably increase how often mutated fish appear.
- Fish during Glitched weather for a +10% chance to catch fish with the Glitched mutation.
- Click the pop-up buttons that appear when you throw the bait. Each cast has a chance to spawn a small button on screen, and pressing it before it disappears raises your chance of a specific mutation.
- Fish during Delulu weather to get a chance at the Delulu mutation.
- Hook Boss Fish for the Champion mutation. Every Boss Fish has a 30% chance to roll Champion, and this mutation appears on Boss Fish only.
Tip: If you only pick up one thing, get the Yinyang Aura. It is the most reliable way to start filling an aquarium with mutated fish.
Stacking rules: which mutations combine
A fish can carry more than one mutation, but only under strict rules. The mutations split into two groups, and how they interact decides your maximum payout.
| Category | Mutations |
|---|---|
| Normal | Gold, Diamond, Plasma, Glitched, Molten, Radioactive |
| Special (stackable) | Delulu, Champion |
A fish can hold only one Normal mutation at a time, so you will never see Molten and Radioactive on the same catch. On top of that single Normal mutation, a fish can also carry both special mutations. Delulu and Champion stack additively over the Normal mutation’s value.
Two examples make the system clear. A Boss Fish that also rolls a Normal mutation can end up with that Normal mutation plus Champion. A fish caught during Delulu weather that already has a Normal mutation can end up with both the Normal mutation and Delulu.
The highest-earning mutation combo
Because Radioactive is the strongest Normal mutation at 8x, the best possible catch pairs it with both special mutations. That gives you the Radioactive x Delulu x Champion combo, the peak earner in the game right now. To even have a shot at it, you need a Boss Fish carrying Radioactive during Delulu weather, with the Champion roll also landing.
You will know a mutation worked because it changes the fish’s appearance and raises its per-second earnings once it is placed in your aquarium. Keep mutation-luck auras equipped, watch for Glitched and Delulu weather, and target Boss Fish when you want the highest-value catches worth chasing.
