Slime Out Fish Fish Index

The Fish Index and Mutation Index are the collection layers of Slime Out Fish (also listed on Roblox as Scale Slimy Fish by Scale the Deeps). Catching a species for Cash is only half the game—logging it in the Index and chasing mutated variants is how you measure long-session progress when rod and knife upgrades start to plateau. This guide explains how those systems work in practice, lists named fish confirmed in creator clips and community runs, and stays honest about what Scale the Deeps has not published publicly.

There is no complete official sell-value table circulating for every species. Community clips cite odds for a few headline fish, but multipliers, exact Cash payouts, and full rarity ladders change with patches. Treat every number below as a clip-cited hint, not a datamined truth. Cross-check live tooltips in your client, and use the fish tier list for practical Cash-versus-collection priorities rather than inventing a fake spreadsheet.

How the Index works

When you land a fish you have never logged, the Index records it. That log is separate from feeding ducks for Cash: you can sell or scrape a fish and still keep the Index entry. The practical habit is simple—glance at the Index after unusual catches, especially during Night specialty windows and weather bursts, so you notice new logs before you autofill inventory with commons.

Index progress rewards curiosity more than pure Cash routing. Early on you will fill commons quickly while following Getting Started. Mid game, gaps cluster around weather-gated and low-odds species. Late game, the Index becomes a checklist you consult before burning Luck Potion II or a Lucky Totem—see bait and boosts for when those consumables are worth opening.

Slime Out Fish longplay covering fish index progress

Mutation Index overview

Mutations are visual and (presumably) value-altering variants of base fish. Confirmed community labels include Frost / frosted, Flaky, and Aurora-mutated looks. Exact Cash or Starlight multipliers for each mutation are unknown—creators show the skins and talk about farming windows, but Scale the Deeps has not posted a public multiplier sheet this wiki can cite with confidence.

What is clear from weather design:

• Aurora advertises roughly 2× mutated spawn pressure plus weather fish.
• Meteor stacks 2× luck, 2× mutated, and premium weather fish.
• Rainy and Thunder raise general luck, which helps rare bases even when they are not mutation-focused skies.

If Mutation Index gaps are your goal, park luck consumables for Aurora and Meteor, then fish hard through the timer. Full sky tables live on Weather Events; Starlight turn-ins after weather fish are covered in Starlight farming.

Named fish examples (confirmed names only)

Use this list as a recognition glossary—not a complete bestiary. Species counts expanded with the June 2026 More Fish branding wave; a full changelog of every added fish is unknown, so we will not invent one. See the More Fish update notes for that honesty.

Name	Notes from clips / community
Common fish	Early Index fillers; Cash backbone while learning scrape timing
Mackerel	Named mid/common target players mention while leveling Index
Clownfish	One creator clip cites roughly 1/64 odds—verify live
Catfish / Furnace Catfish	Named variants; treat furnace form as a distinct Index line if your client separates them
Swordfish	Ultra-rare citation around 1/400k in one clip—expect long dry spells
Thunder Tuna	Labeled Secret in community talk
Meteor Blade	Secret / limited-style catch tied to Meteor-era content
Thunder Piranha	Mythic tag in creator coverage
Polar Ribbon Fish	Mythic tag; cold/aurora aesthetic in showcases
Thunder Lionfish	Thunder-associated named catch
Blue Snapper Catfish	Named Index target beyond basic Catfish
Octopus	Named specialty catch players chase for Index completion

Odds like 1/64 or 1/400k are clip citations, not guaranteed live rates. Patches, bait, rod luck, and server weather all move the needle. Never plan a whole economy around an unverified Swordfish payout.

Farming for Index vs Mutation Index

Index (new base species)

1. Keep inventory space open so a new fish is not rejected mid-cast.
2. Rotate through Night and weather zones instead of AFK-casting one Sunny pier forever.
3. Upgrade rod depth/luck only as fast as your knife can perfect-scrape—see Perfect Scaling and the knives tier list.
4. After Aurora/Thunder/Meteor, check whether weather exclusives filled Index rows before you dump everything into ducks.

Mutation Index

1. Prefer Aurora and Meteor windows.
2. Pre-load bait capacity so short timers yield more rolls—timing tips sit on bait and boosts.
3. Use Luck Potion II / Lucky Totem only when the sky already multiplies mutations.
4. Log Frost/frosted, Flaky, and Aurora-mutated hits when they appear; do not assume every shiny texture is a tracked mutation until the Index confirms it.

Cash value honesty

Scraping and feeding still pay Cash for almost everything you catch. Higher rarity and mutated looks feel more valuable in creator showcases, but without an official sell table this wiki will not publish invented Cash columns. Practical guidance:

• Perfect scrapes matter on every fish you intend to feed—dull knives leak Cash even on “rare” hauls.
• Weather fish should usually go to Thunder Siam for Starlight before you treat them as ordinary duck food—see Starlight farming.
• For “what is worth chasing for money,” use the fish tier list which ranks practical targets using only named fish and known systems.

Session plan for collectors

1. Redeem codes and clear shop bottlenecks so you are not Index-hunting on Beginner gear.
2. Note the weather timer; if Aurora or Meteor is close, delay long Sunny shop AFKs.
3. Fish the event, prioritize weather fish and unfamiliar silhouettes, then scrape leftovers for Cash.
4. Open Index + Mutation Index, mark new logs, and decide whether the next consumable burn is justified.
5. On Sunny downtime, process backlog and rebalance rod vs knife with How to Earn Cash.

Common mistakes

• Assuming every YouTube odds callout is patch-proof.
• Burning luck potions on Sunny while Mutation Index gaps remain.
• Ignoring Thunder Siam because “Index only cares about catching,” then missing Starlight progression tied to the same weather fish.
• Chasing Swordfish-tier citations before Kitchen Knife and Toy Rod fundamentals are stable.
• Inventing personal sell charts from one lucky Meteor clip and teaching them as fact.

Related pages

• Weather Events — Sky multipliers and weather-fish counts.
• Starlight farming — Thunder Siam turn-ins and shop sinks.
• Fish tier list — Cash vs collection priorities.
• Getting Started — Day-one loop before deep Index grinding.
• Bait and boosts — When luck items and bait capacity help rolls.
• More Fish update — June 2026 species expansion context.

Fill the Index patiently, farm mutations when the sky agrees, and keep sell-value claims humble until Scale the Deeps publishes hard numbers.