[leebca]

I hope you are not being fooled by the discoloration of the Tang. Most Tangs when they are stressed change colors, darken, lighten, change patterns to spots, stripes, etc. It is natural for them to do this. I didn't think about this earlier, but I just want to be sure you know the difference between a Tang's reaction to stress and an actual problem.

Anyway. . .Some of the facts regarding Marine Ich can be found in my post:
Marine Ich - Myths and Facts

If there is the Marine Ich parasite (Cryptocaryon irritans) in the display tank AND no (ZERO) new Marine Ich parasites get into the display aquarium, then in about 11 months the Marine Ich in the display aquarium is no longer strong enough to infect fish. The parasite goes through so many generations and weakens as it does, cut off from any new sources of the parasite.

As you'll note from the above referenced post, a fish that has developed resistance to Marine Ich when stressed, can still be overcome by the disease. What kinds of stress? Even as something as relatively benign as the introduction of a new fish into the display.

[anthias]

thank you very much lee for the threads , my tang is doing fine I hope I not lose him I note that his fins are reginrating and this is good sign I hope.