To use Bash in such circumstances you just exit Fish via ^d or type exit. The bad thing about is you execute a Bash shell which uses resources. But with today's

To use Bash in such circumstances you just exit Fish via ^d or type exit. The bad thing about is you execute a Bash shell which uses resources. But with today's RAM even on a smartphone this wouldn't matter. The convenience and safety (to have a working default shell) is worth it. You can use Fish on any system where Nix runs on, btw. For example, I use it on Synology's DSM.