Honestly after my 3rd died
I just took him out o water he isn't turning back
Now and is suffering
sorry for him to suffer but I had a foxface, blond tang and a week ago coral beauty who all got this gill parasite that killed them in less then 24hrs it scared me and puzzled me because everyone else seemed to be fine which was weird. Good thing he is in the quarantine tank cause I'm in a load of mess for it happening in the display tank
maybe try Melafix and the natural herbals in the quarantine tank it really helped my hippos tang fin grow back and I had good success with it
the only downside is because it's natural it takes a little while to work.