I know people should quarantine all fish. But I have a question. Even with quarantine fish cant ich and other parasites get in tank? Maybe from a new coral or a new piece of live rock you add??? Most LFS have fish in all tanks that have corals or live rock. I cant imagine we quarantine new corals and live rocks for 4-6 weeks... What about invertebrate? I know they don't get ich but there is a chance one egg or something is just catching a ride for a few hours??? And a lot of people use live sea water from the ocean. My LFS carries natural salt water from the ocean. I heard natural ocean has ich. So couldn't you add ich to your tank from a simple water change???
Yes, the parasite can enter the tank through contaminated live rocks, sand, hard shelled inverts such as snails, hard coral or coral attached to rocks. Yes, people do even QT their coral, etc., before introducing it in to their display tank; though the timeframe for that would be less then dealing with infected fish since non-fish can not host the parasite, therefore the life cycle of ich is cut short on non-fish. Also, I feel the likelihood of infection is reduced just because the parasite is absent the host fish which it requires to complete its life-cycle.
I have to admit I QTed fish but not the rest. I was cautious about where my stuff came from (such as not knowing getting items from tanks shared with fish).
I would never use ocean water. There is absolutely no way of knowing what comes in the ocean water, including pollution.
