All 10 mutant fish in one list, with their type, time of day and sell price. Below it, each mutant is compared side by side with the normal fish the in-game encyclopedia relates it to, followed by what sets mutants apart in the Grinder and the main quests that ask you to catch them.
Mutant fish list
10 fish are mutants. Open a fish for where to catch it (with a map), its bait and Grinder materials.
| Mutant fish | Type | Time of day | Sell price | Related normal fish |
|---|---|---|---|---|
 Necrosoft | Peaceful | Night only |  42–97 |  Softgrazer(Mutated form)Compare ↓ |
 Rammfish | Predatory | Day & night | 74–159 | — |
 Harpy | Predatory | Night only | 40–80 | — |
 Stonegnawer | Predatory | Night only | 66–142 |  Bully(Mutated relative)Compare ↓ |
 Swallower | Predatory | Night only | 39–65 |  Bloodgill(Compared in its description)Compare ↓ |
 Crackback | Predatory | Night only | 40–86 |  Gleamer(Mutated form)Compare ↓ |
 Glowbug | Predatory | Day & night | 57–132 | — |
 Cryptmaw | Predatory | Night only | 47–109 | — |
 Gravedigger | Peaceful | Night only | 60–139 | — |
 Shardback | Predatory | Day & night | 59–138 | — |
Sell price: what a merchant pays for one fish. The price differs from fish to fish; the range runs from the lowest to the highest price.
The encyclopedia entries of 
Rivetback and 
Bonescar also mention mutation, but they are not mutants, and the Grinder gives them ordinary 
Fish Meat instead of 
Mutant Fish Meat. They are not included in this list.
Normal vs. mutant fish compared
The in-game encyclopedia describes how these 4 pairs are related. Each table puts the normal fish and the mutant side by side: type, sell price, time of day, bait and Grinder materials per fish.
- Mutated form: the encyclopedia says the mutant is the normal fish changed by mutation.
- Mutated relative: the encyclopedia calls the mutant a mutated relative of the normal fish.
- Compared in its description: the mutant's encyclopedia entry mentions the normal fish as a comparison.
SoftgrazerNecrosoft
| Mutated form | Normal fish Softgrazer | |
|---|---|---|
| Type | Peaceful | Peaceful |
| Sell price | 15–28 | 42–97 |
| Time of day | Day & night | Night only |
| Bait | ||
| Grinder materials (per fish) | ||
| Fish Meat | ×1 | — |
 Chromatic Scales | ×1 | ×3 |
| Mutant Fish Meat | — | ×1 |
 Leeches | — | ×2 |
BullyStonegnawer
| Mutated relative | Normal fish Bully | |
|---|---|---|
| Type | Predatory | Predatory |
| Sell price | 53–113 | 66–142 |
| Time of day | Day & night | Night only |
| Bait | ||
| Grinder materials (per fish) | ||
 Jaws | ×2 | ×2 |
 Bone Plate | ×3 | ×3 |
| Fish Meat | ×3 | — |
| Leeches | — | ×3 |
| Mutant Fish Meat | — | ×2 |
BloodgillSwallower
| Compared in its description | Normal fish Bloodgill | |
|---|---|---|
| Type | Predatory | Predatory |
| Sell price | 23–50 | 39–65 |
| Time of day | Day & night | Night only |
| Bait | ||
| Grinder materials (per fish) | ||
| Fish Meat | ×3 | — |
| Jaws | ×2 | ×2 |
| Mutant Fish Meat | — | ×1 |
| Leeches | — | ×2 |
GleamerCrackback
| Mutated form | Normal fish Gleamer | |
|---|---|---|
| Type | Predatory | Predatory |
| Sell price | 29–62 | 40–86 |
| Time of day | Day & night | Night only |
| Bait | ||
| Grinder materials (per fish) | ||
| Fish Meat | ×3 | — |
| Jaws | ×2 | ×2 |
| Mutant Fish Meat | — | ×1 |
| Leeches | — | ×2 |
The encyclopedia also calls Harpy a kin of 
Harpooner, and says some 
Shovelnose mutate into Gravedigger. Open each fish's page to compare them.
What sets mutant fish apart
- In the Grinder, every mutant fish gives Mutant Fish Meat and Leeches. Normal fish give Fish Meat instead, and none of them give Mutant Fish Meat or Leeches.
- Mutant Fish Meat is a crafting material for Coral fishing rod, Clinging Pincer and First aid kit. Leeches are used for Sliding fishing line, Clinging Pincer and Pipecross.
- 7 of the 10 mutants can only be caught at night; Rammfish, Glowbug and Shardback can be caught day and night. Every normal fish can also be caught during the day.
- 8 of the mutants are predatory and 2 are peaceful (Necrosoft and Gravedigger).
The in-game description of Mutant Fish Meat:
Fish flesh warped by the Blight. Its tough fibers ooze tainted essence, attracting scavengers and predators. Making soup from this meat is not recommended!
Main quests that ask for mutant fish
These main quests ask you to catch mutant fish. Quest names and objectives are the in-game text, listed in story order.
| Quest | Objective | Mutant fish |
|---|---|---|
| Catch a Mutant Fish | Catch a Cryptmaw at night | Cryptmaw |
| The Experimenters | Catch a Gravedigger at night | Gravedigger |
| Fish for the Essence | Catch three deaf fish in Jacqueline's Grotto | Shardback |
| Fish for the Essence | Catch three deep fish in Lilo's Cave | Glowbug |
Related tools
- Fish List: opens with only mutants shown
- Fishing Spots Map: every fishing spot on the map, with the time of day and required rod parts
- Bait Guide: which bait each fish takes, including the mutants