I have heard anywhere from 6 weeks to 9 months - OUCH, unfortunatley - The nine month part is because the ich can go into a hibernation type mode? Hopefully someone else can explain it a little better then me.
I just lost all my fish, golden flake angel, mistery wrase, perperl tung etc.
I am now waiting 21 day for the ice peresite to be gone, with the UV working.
It take 21 days to finish with the ice cycle to go.
On average I would go with 6 weeks.
But if you do not QT all your new fish with a full course of hypo or copper treatment, then you've just reintroduced the parasite anyway...
well
here is wha happened
i was out of town for a week and had 3 fish in my 29g QT
one died and the person feeding my fish did not take the dead fish out
i came home and the 180 levels were perfect and the 29g was horrible!
so i took my 2 fish and put them in my DT
Ahh so many tanks it is my 55g
it had fish in it for only 2 1/2 days after i noticed ick develping on the fish
now they are all doing better treated in the QT again
do i still have to wait 6 weeks because there was only ick for 2 days
well what I did was took out the LR and put it in a 10g with powerheads w/ DT water
then i took out about 15 more gallons of water and put treated fresh water in to lower the salinity
So now the DT has no fish and a spec grav of 1.019- i though it would help kill the ick
i will wait about 4 weeks now???