diff --git a/modules/programs/fish.nix b/modules/programs/fish.nix
index ad9e8d93..88164685 100644
--- a/modules/programs/fish.nix
+++ b/modules/programs/fish.nix
@@ -250,11 +250,13 @@ let
           description = "Specify the bind mode that the bind is used in";
           type =
             with types;
-            nullOr (enum [
-              "default"
-              "insert"
-              "paste"
-            ]);
+            nullOr (
+              either (enum [
+                "default"
+                "insert"
+                "paste"
+              ]) str
+            );
           default = null;
         };
         command = mkOption {
@@ -279,11 +281,13 @@ let
           description = "Change current mode after bind is executed";
           type =
             with types;
-            nullOr (enum [
-              "default"
-              "insert"
-              "paste"
-            ]);
+            nullOr (
+              either (enum [
+                "default"
+                "insert"
+                "paste"
+              ]) str
+            );
           default = null;
         };
         erase = mkEnableOption "remove bind";
diff --git a/tests/modules/programs/fish/binds.nix b/tests/modules/programs/fish/binds.nix
index 65e8a264..d41766ba 100644
--- a/tests/modules/programs/fish/binds.nix
+++ b/tests/modules/programs/fish/binds.nix
@@ -14,6 +14,12 @@
           command = "exit";
         };
 
+        # Allow arbitrary modes
+        "f" = {
+          mode = "something-non-default";
+          command = "exit";
+        };
+
         "ctrl-c" = {
           mode = "insert";
           command = [
@@ -57,6 +63,8 @@
           "bind --preset alt-s 'fish_commandline_prepend sudo"
         assertFileContains home-files/.config/fish/functions/fish_user_key_bindings.fish \
           "bind --mode visual ctrl-d exit"
+        assertFileContains home-files/.config/fish/functions/fish_user_key_bindings.fish \
+          "bind --mode something-non-default f exit"
       '';
     };
   };