Oh Laurie i am soooo sorry
We had Vibrio in our tank a little over a year ago and unfortunetly i watched our fish do the same as yours. They died a painful death and by the time i figured out what was going on it was to late..It is funny how they do things when they are sick and dieing. All my anthias died together in the back corner all in a span of about 5mins. And my regal angel was the same as your 6line. Forever to dig her out of the rocks and about 5mins to die in quarintine.
If it is helpful at all that checkerboard made it through that Vibrio without a hickup...Hes a tough little bugger!