No.. but if you want to preserve your fixer, then yes. I have always used a stop, be it Ilford's indicator stop bath, or DIY citric acid, or vinegar, for films and paper.
Nah - but I left the screwup for all to see!
I could probably have still edited it even if I wasn't a moderator.
If we toned NB23, what tone do you think we might get?