I've been using fish at home and bash at work for almost a decade now, and it's been fine — and because I'm at a fish shell on my own computer far more often than I'm at a bash shell on a work server, I'm willing to take the slight productivity hit there, because I gain overall.

The thing is, when I picked up fish, I couldn't forget my existing bash knowledge. I still have to write normal bash-dialect shell scripts, and with the fish syntax being so much nicer and simpler, the two can happily co-exist in my head. Occasionally I'll hit Up to search through history instead of Control-R, but I quickly realise what I've done and use the bash keybinding instead. And the only fish aliases I missed were 'l', 'll', and 'la', which I just manually copied over without bothering with the rest.

If I had to use bash more often at work... I'd still use fish at home after all the time I've sunk into it, but YMMV.