diff --git a/data/json/harvest.json b/data/json/harvest.json
index 9d955e91b5e86..45e955ea96a07 100644
--- a/data/json/harvest.json
+++ b/data/json/harvest.json
@@ -37,6 +37,15 @@
       { "drop": "bone", "type": "bone", "mass_ratio": 0.1 }
     ]
   },
+  {
+    "id": "mutant_fish",
+    "type": "harvest",
+    "entries": [
+      { "drop": "mutant_meat", "type": "flesh", "mass_ratio": 0.38 },
+      { "drop": "liver", "type": "offal", "mass_ratio": 0.01 },
+      { "drop": "bone", "type": "bone", "mass_ratio": 0.1 }
+    ]
+  },
   {
     "id": "shellfish",
     "type": "harvest",
@@ -47,6 +56,15 @@
       { "drop": "chitin_piece", "type": "skin", "mass_ratio": 0.1 }
     ]
   },
+  {
+    "id": "mutant_shellfish",
+    "type": "harvest",
+    "message": "You carefully crack open its exoskeleton to get at the flesh beneath",
+    "entries": [
+      { "drop": "mutant_meat", "type": "flesh", "mass_ratio": 0.32 },
+      { "drop": "chitin_piece", "type": "skin", "mass_ratio": 0.1 }
+    ]
+  },
   {
     "id": "mon_broken_cyborg",
     "type": "harvest",
diff --git a/data/json/monsters/fish.json b/data/json/monsters/fish.json
index 5bd7194039897..5675c58fa8a5a 100644
--- a/data/json/monsters/fish.json
+++ b/data/json/monsters/fish.json
@@ -617,7 +617,7 @@
     "melee_cut": 2,
     "dodge": 5,
     "luminance": 0,
-    "harvest": "fish_large",
+    "harvest": "mutant_fish",
     "reproduction": { "baby_egg": "egg_fish", "baby_count": 1, "baby_timer": 6 },
     "baby_flags": [ "SPRING" ],
     "death_function": [ "NORMAL" ],
@@ -646,7 +646,7 @@
     "melee_cut": 2,
     "dodge": 5,
     "luminance": 0,
-    "harvest": "fish_large",
+    "harvest": "mutant_fish",
     "reproduction": { "baby_egg": "egg_fish", "baby_count": 2, "baby_timer": 150 },
     "baby_flags": [ "AUTUMN" ],
     "death_function": [ "NORMAL" ],
@@ -676,7 +676,7 @@
     "dodge": 6,
     "vision_day": 1,
     "vision_night": 30,
-    "harvest": "fish_large",
+    "harvest": "mutant_fish",
     "reproduction": { "baby_egg": "egg_fish", "baby_count": 2, "baby_timer": 19 },
     "baby_flags": [ "SPRING", "SUMMER", "AUTUMN", "WINTER" ],
     "path_settings": { "max_dist": 5 },
diff --git a/data/json/monsters/monsters.json b/data/json/monsters/monsters.json
index 4ae2df315450c..b0c15d3414c7c 100644
--- a/data/json/monsters/monsters.json
+++ b/data/json/monsters/monsters.json
@@ -82,7 +82,7 @@
     "armor_cut": 30,
     "vision_day": 30,
     "vision_night": 20,
-    "harvest": "shellfish",
+    "harvest": "mutant_shellfish",
     "path_settings": { "max_dist": 50 },
     "special_attacks": [ [ "SHRIEK_ALERT", 6 ], [ "SHRIEK_STUN", 1 ] ],
     "anger_triggers": [ "PLAYER_CLOSE", "HURT" ],
@@ -2107,7 +2107,7 @@
     "armor_cut": 18,
     "vision_day": 30,
     "vision_night": 15,
-    "harvest": "shellfish",
+    "harvest": "mutant_shellfish",
     "path_settings": { "max_dist": 50 },
     "special_attacks": [ [ "SHRIEK_ALERT", 6 ], [ "SHRIEK_STUN", 1 ] ],
     "anger_triggers": [ "PLAYER_CLOSE", "FRIEND_DIED", "FRIEND_ATTACKED", "HURT" ],