diff --git a/cli/fish/config.fish b/cli/fish/config.fish
index fdb6ac5..c824a59 100644
--- a/cli/fish/config.fish
+++ b/cli/fish/config.fish
@@ -3,6 +3,7 @@
 if status is-interactive
     # === default programs
     set -gx EDITOR vim
+    set -gx TMUX_SHELL (command -v fish)
 
     # === fzf configuration
     set -gx FZF_DEFAULT_COMMAND 'ag -g ""'
diff --git a/cli/tmux/tmux.conf b/cli/tmux/tmux.conf
index 1fbcd40..b681edf 100644
--- a/cli/tmux/tmux.conf
+++ b/cli/tmux/tmux.conf
@@ -18,7 +18,7 @@ set-option -g set-titles-string "#S / #W"
 ############################
 setw -g mode-keys vi
 set -g status-keys vi
-set -g default-shell $SHELL
+set -g default-shell $TMUX_SHELL
 # set -g prefix C-h
 bind c new-window -c '#{pane_current_path}'
 bind '"' split-window -c '#{pane_current_path}'