Official conclusion of this thread... the FM was somewhat active briefly this morning, swimming a bit but intermittently sinking to the bottom for a crash landing... kind of like a lead balloon. An hour later he wasn’t able to right himself, made a last gasp effort by putting him in a shallow filled bucket with air but he didn’t pull through. I don’t think I got the meds into his system effectively enough or soon enough unfortunately.
So my last question - I am thinking I should complete the general cure treatment cycle (3 treatments over a few days as it says on directions) and keep the other fish on hex shield for the duration of that cycle. Then big water change and resume normal conditions. Thoughts?
Bummed to lose the fish, hopefully this thread helps someone in the future.