diff --git a/fish_prompt.fish b/fish_prompt.fish
index 4150ab3..197d81e 100644
--- a/fish_prompt.fish
+++ b/fish_prompt.fish
@@ -801,6 +801,20 @@ function __bobthefish_prompt_desk -S -d 'Display current desk environment'
     set_color normal
 end
 
+function __bobthefish_prompt_nix -S -d 'Display current nix environment'
+    [ "$theme_display_nix" = 'no' -o -z "$IN_NIX_SHELL" ]
+    and return
+
+    if [ "$IN_NIX_SHELL" = "impure" ]
+        set say_what "nix"
+    else
+        set say_what "pure"
+    end
+
+    __bobthefish_start_segment $color_nix
+    echo -ns $nix_glyph' ' "$say_what" ' '
+    set_color normal
+end
 
 # ==============================
 # VCS segments
@@ -1000,6 +1014,7 @@ function fish_prompt -d 'bobthefish, a fish theme optimized for awesome'
     __bobthefish_prompt_user
 
     # Virtual environments
+    __bobthefish_prompt_nix
     __bobthefish_prompt_desk
     __bobthefish_prompt_rubies
     __bobthefish_prompt_virtualfish
diff --git a/functions/__bobthefish_colors.fish b/functions/__bobthefish_colors.fish
index 0afe3b8..9176473 100644
--- a/functions/__bobthefish_colors.fish
+++ b/functions/__bobthefish_colors.fish
@@ -33,6 +33,7 @@ function __bobthefish_colors -S -a color_scheme -d 'Define colors used by bobthe
       set -x color_virtualfish              brblue $colorfg --bold
       set -x color_virtualgo                brblue $colorfg --bold
       set -x color_desk                     brblue $colorfg --bold
+      set -x color_nix                      brblue $colorfg --bold
 
     case 'terminal-light*'
       set -l colorfg white
@@ -63,6 +64,7 @@ function __bobthefish_colors -S -a color_scheme -d 'Define colors used by bobthe
       set -x color_virtualfish              brblue $colorfg --bold
       set -x color_virtualgo                brblue $colorfg --bold
       set -x color_desk                     brblue $colorfg --bold
+      set -x color_nix                      brblue $colorfg --bold
 
     case 'terminal2' 'terminal2-dark*'
       set -l colorfg black
@@ -93,6 +95,7 @@ function __bobthefish_colors -S -a color_scheme -d 'Define colors used by bobthe
       set -x color_virtualfish              brblue $colorfg --bold
       set -x color_virtualgo                brblue $colorfg --bold
       set -x color_desk                     brblue $colorfg --bold
+      set -x color_nix                      brblue $colorfg --bold
 
     case 'terminal2-light*'
       set -l colorfg white
@@ -123,6 +126,7 @@ function __bobthefish_colors -S -a color_scheme -d 'Define colors used by bobthe
       set -x color_virtualfish              brblue $colorfg --bold
       set -x color_virtualgo                brblue $colorfg --bold
       set -x color_desk                     brblue $colorfg --bold
+      set -x color_nix                      brblue $colorfg --bold
 
     case 'zenburn'
       set -l grey   333333 # a bit darker than normal zenburn grey
@@ -159,6 +163,7 @@ function __bobthefish_colors -S -a color_scheme -d 'Define colors used by bobthe
       set -x color_virtualfish              $blue $grey --bold
       set -x color_virtualgo                $blue $grey --bold
       set -x color_desk                     $blue $grey --bold
+      set -x color_nix                      $blue $grey --bold
 
     case 'base16-light'
       set -l base00 181818
@@ -206,6 +211,7 @@ function __bobthefish_colors -S -a color_scheme -d 'Define colors used by bobthe
       set -x color_virtualfish              $base0D $colorfg --bold
       set -x color_virtualgo                $base0D $colorfg --bold
       set -x color_desk                     $base0D $colorfg --bold
+      set -x color_nix                      $base0D $colorfg --bold
 
     case 'base16' 'base16-dark'
       set -l base00 181818
@@ -253,6 +259,7 @@ function __bobthefish_colors -S -a color_scheme -d 'Define colors used by bobthe
       set -x color_virtualfish              $base0D $colorfg --bold
       set -x color_virtualgo                $base0D $colorfg --bold
       set -x color_desk                     $base0D $colorfg --bold
+      set -x color_nix                      $base0D $colorfg --bold
 
     case 'solarized-light'
       set -l base03  002b36
@@ -300,6 +307,7 @@ function __bobthefish_colors -S -a color_scheme -d 'Define colors used by bobthe
       set -x color_virtualfish              $cyan $colorfg --bold
       set -x color_virtualgo                $cyan $colorfg --bold
       set -x color_desk                     $cyan $colorfg --bold
+      set -x color_nix                      $cyan $colorfg --bold
 
     case 'solarized' 'solarized-dark'
       set -l base03  002b36
@@ -347,6 +355,7 @@ function __bobthefish_colors -S -a color_scheme -d 'Define colors used by bobthe
       set -x color_virtualfish              $cyan $colorfg --bold
       set -x color_virtualgo                $cyan $colorfg --bold
       set -x color_desk                     $cyan $colorfg --bold
+      set -x color_nix                      $cyan $colorfg --bold
 
     case 'light'
       #               light  medium dark
@@ -387,6 +396,7 @@ function __bobthefish_colors -S -a color_scheme -d 'Define colors used by bobthe
       set -x color_virtualfish              $blue[2] $grey[1] --bold
       set -x color_virtualgo                $blue[2] $grey[1] --bold
       set -x color_desk                     $blue[2] $grey[1] --bold
+      set -x color_nix                      $blue[2] $grey[1] --bold
 
     case 'gruvbox'
       #               light  medium  dark  darkest
@@ -426,6 +436,7 @@ function __bobthefish_colors -S -a color_scheme -d 'Define colors used by bobthe
       set -x color_virtualfish           $blue[2] $fg[2] --bold
       set -x color_virtualgo             $blue[2] $fg[2] --bold
       set -x color_desk                  $blue[2] $fg[2] --bold
+      set -x color_nix                   $blue[2] $fg[2] --bold
 
     case 'dracula' # https://draculatheme.com
       set -l bg           282a36
@@ -467,6 +478,7 @@ function __bobthefish_colors -S -a color_scheme -d 'Define colors used by bobthe
       set -x color_virtualfish           $comment $bg --bold
       set -x color_virtualgo             $cyan $bg --bold
       set -x color_desk                  $comment $bg --bold
+      set -x color_nix                   $cyan $bg --bold
 
     case '*' # default dark theme
       #               light  medium dark
@@ -508,6 +520,7 @@ function __bobthefish_colors -S -a color_scheme -d 'Define colors used by bobthe
       set -x color_virtualfish              $blue[2] $grey[1] --bold
       set -x color_virtualgo                $go_blue $black --bold
       set -x color_desk                     $blue[2] $grey[1] --bold
+      set -x color_nix                      $blue[2] $grey[1] --bold
   end
 end
 
@@ -533,6 +546,7 @@ function __bobthefish_user_color_scheme_deprecated
   set -q __color_virtualfish;           or set -l __color_virtualfish           005faf cccccc --bold
   set -q __color_virtualgo;             or set -l __color_virtualgo             005faf cccccc --bold
   set -q __color_desk;                  or set -l __color_desk                  005faf cccccc --bold
+  set -q __color_nix;                   or set -l __color_nix                   005faf cccccc --bold
 
   set_color black -b red --bold
   echo "The 'user' color scheme is deprecated."
@@ -569,6 +583,7 @@ function __bobthefish_user_color_scheme_deprecated
   set -x color_virtualfish           $__color_virtualfish
   set -x color_virtualgo             $__color_virtualgo
   set -x color_desk                  $__color_desk
+  set -x color_nix                   $__color_nix
 end"
 
   echo
diff --git a/functions/__bobthefish_glyphs.fish b/functions/__bobthefish_glyphs.fish
index 30764f5..e5d065a 100644
--- a/functions/__bobthefish_glyphs.fish
+++ b/functions/__bobthefish_glyphs.fish
@@ -21,6 +21,7 @@ function __bobthefish_glyphs -S -d 'Define glyphs used by bobthefish'
 
   set -x ruby_glyph              ''
   set -x go_glyph                ''
+  set -x nix_glyph               ''
 
   # Desk glyphs
   set -x desk_glyph              \u25F2
@@ -59,6 +60,7 @@ function __bobthefish_glyphs -S -d 'Define glyphs used by bobthefish'
     set detached_glyph   \uF417
     set tag_glyph        \uF412
 
+    set nix_glyph        \uF313 # nf-linux-nixos
     set virtualenv_glyph \uE73C ' '
     set ruby_glyph       \uE791 ' '
     set go_glyph         \uE626 ' '