Ok, so maybe the “anti-prophylactic” thread is getting to me... but, I’m pretty certain that we would have known by now if she had velvet.
I think if you want to do 30 days in hypo, and then another 2-3 weeks of observation and good feedings... and if nothing shows by then you should be relatively safe.
If it were a wrasse or pretty much any other fish I’d probably still suggest copper prophylactically... but blue tangs are VERY good at showing signs of ich/velvet, so at this point I think I would be comfortable with the hypo treatment and observational QT.
That is completely up to you though :) If you’d prefer to do the copper we can walk you through it.
I don’t expect she will need antibiotics now. With the MB treatment and flukes finally gone, she looks pretty good. We can see how it goes without the MB though.