You can just type in anything you'd like as when using Ctrl+R and then just press the up arrow key to perform a fuzzy match in your history.
I'm sure it uses inputrc or similar, giving you a thing like:
$if mode=emacs
"\e[A": history-search-backward
"\e[B": history-search-forward
$endif
aka, type "fish" and press up arrow to only go through history that starts with "fish"also, how would you configure fish to use something that doesn't lean on arrows? ^r has its own useful power that can be separate from my use-case of arrows mentioned above, if not just bc you don't have to move off the homerow ;)
edit: this originally said ^D, which is EOF, not autocomplete :)