Thanks, Littlefish. About half an hour ago, I moved her into the hospital tank as a "trial run" with eSHa 2000. I felt terrible, as the cardinals all shoaled up tightly to escape the jug, as though protecting her. Everyone else in the tank seemed to volunteer to get in it but the cardinals were having none of it. There was water everywhere as attempts to guide her in with a net resulted uprooting of the silk plants, wood getting caught against the net, etc. Eventually most of the cardinals ended up in the jug together and I had to try to get them out and leave her in, to transfer her to the hospital tank. She looked calmer in there than when in an Epsom salt bath, but I'm in the other room now and keeping my distance from Mr FCMF who always (and thankfully only ever) seems to get annoyed with me when water spillages occur and the hospital tank is in use and taking up valuable space.
Updated to add: Just nipped through to check up on her. She was at one end of the tank, watching her tankmates in the main tank. Not sure if it was intrigue, comfort, wistfulness, envy or frustration, or to what degree fish might experience these emotions - certainly they can be very inquisitive. Uncharacteristically, they were in an unusual location at the front edge of the tank, so must have been watching her too.