diff --git a/nixos/fish.nix b/nixos/fish.nix
index de8b828..440a3db 100644
--- a/nixos/fish.nix
+++ b/nixos/fish.nix
@@ -55,7 +55,12 @@
 
   programs.bash = {
     interactiveShellInit = ''
-      if [[ -z ''${BASH_EXECUTION_STRING} ]]
+      # the first arguement in the if statement check that the parent process is not a fish shell.
+      # this allows spawning a bash shell inside a fish shell without the inner-most bash shell launching a fish shell
+      # however this also means that nix-shell starts a bash shell unless you use `nix-shell [args] --run fish`
+      # or run `fish` as the first command when entering nix-shell
+
+      if [[ $(${pkgs.procps}/bin/ps --no-header --pid=$PPID --format=comm) != "fish" && -z ''${BASH_EXECUTION_STRING} ]]
       then
         shopt -q login_shell && LOGIN_OPTION='--login' || LOGIN_OPTION=""
         exec ${pkgs.fish}/bin/fish $LOGIN_OPTION