I have a powder blue tang that eats good buy has ick. It has been 5 weeks now so i tried this ginger and no change after a week. I even added fresh garlic and vitamins .as a food soak every day on dry and pellet food. He still has it.
I posted this reply under Reef Fish Diseases but, thought I wouls copy and paste it here. This has (so far) worked for me and is by no means a Scientific study nor am I recommending this as an alternative for QT or Copper. I did not have the luxury of a QT and had an ich outbreak in my DT and this has helped me and so, I offer it as an alternate therapy for those who cannot remove their affected fish or do not have a QT.
After three weeks of a Blue Hippo being completely covered in ich in my DT and not having a QT, I tried a different route.
I treated 5 days with Fishkeeper additive for Marine and Reef (made by Tropical Science), Seachem Metronidazole and Seachem Focus (Nitrofurantoin) along with Garlic Guard in their food at every feeding. I feed 3-5 times a day and added to both frozen and flake food. No one turned their nosed up at the medicated food.
The ich spots dissapperared 2 days into treatment. I used the Fish Keeper additive for 5 days and the Metronidazole and Focus for a total of 10 days.
This is a full reef tank with SPS, LPS, Gorgonians, and a LTA. There have been NO ILL EFFECTS to any of the reef inhabitants including my snails, hermit crabs and many ornamental shrimp.
It has now been 40+ days since completion of that therapy. There is no sign of ich. The tang is fatter and even more active than before. All the fish are still healthy and I did not have to treat the DT. I stopped the Metronidazole and Focus after 10 days. There has been no recurrence of spots after 3 solid weeks of heavy ich infestation of my Blue Tang.
I 'tested' the tank by adding a One-spot Foxface 2 weeks ago. No recurrence of the ich and no signs of ich on the new fish. I cannot say that the ich has been irradicated. There is no way to know but, a test by adding a new fish did not trigger a stress recurrence in the blue tang or an outbreak in the new Foxface who was very obviously stressed by demonstrating 'blochty' coloration, not feeding and hiding for 3 days before coming out to eat.
I know this is not the recommended course of action but, it was just about my only recourse and, in this case, it worked well. The ich was constant and the poor tang was covered from head to tail every day with hundreds of white spots, never a day without spots for 3 weeks. Two days into this treatment he lost all of the spots. Ich is a protozoan and we use Metronidazole on humans to treat protozoan infections. It just made sense to try it in the food and it seems to be working.
I would not hesitate to use this method again of recommend to others to try even in a full reef tank.