How long do you typically have a fish in quarantine? Since the answer is somewhat dependent on the circumstances... in my current case i have just picked up a new tang from an established tank (owner is getting out of the hobby). The tank in question did apparently crash aprox 2 months ago from an ATO mishap but this tang and the other inhabitants were well on the way to recovery before i got him. According to the previous owner this tang has never had ich, has been eating like a pig, and i saw first hand how energetic he was. I've now had him for 3 days, after being ski-dish the first 2 days he's now eating good and swimming happily around his tank. No signs of ich or anything else as of yet... Just not sure how long to wait for any signs of trouble.