Rescue/conversion of the zhistory for fish
Change to fish shell.
chsh -s /bin/fish
Change name to work with converter, .zhistory is your backup.
cp .zhistory .zsh_history
Make backup from fish_history, if nesseccery.
cp .local/share/fish/fish_history .local/share/fish/fish_history.bak
Install pip if needed.
sudo pacman -Syu python-pip
Install converter.
pip install zsh-history-to-fish
Convert the history and commands.
zsh-history-to-fish