Ich aftermath... what to do now?

[Reef Pilot]

Originally Posted by mrhasan

I just don't get it; how can a sick fish which is stressed already is further stressed by catching it, putting it in a small tank and doing things like jumbling between tanks, making it live in a hyposaline water or passing strong medicine like copper through its gill can help. Sure a surgery can be performed with no anesthesia but how would it feel? Maybe I am over-pessimist and rely overly on good husbandry.....

That's why I advocate quarantine as prevention with a standby QT already cycled and ready to accept fish. I agree that transferring fish already infected to a hastily set up QT has a good chance of failing.

You should read this article, too. It further explains how hypo reduces stress in fish and is a good proactive routine with new fish.
http://www.advancedaquarist.com/2007/6/fish

[asylumdown]

At this stage, it looks like the fish in your QT have developed a certain amount immunity to the parasite, which is why you're no longer seeing any active pustules. Acquired immunity has been demonstrated in a bunch of fish in the literature, but the parasite is definitely still in your system.

If you have no plans of going through the extremely intensive and time consuming process of taking the remaining fish out and treating them in QT while fallowing your tank for 10-12 weeks, your best bet for re-stocking is to not buy any fish that are known to be highly susceptible to ich, as it's in your system. IE, don't buy any more tangs.