Jenglish: not challenging you at all, but are you stating researched facts, observation, opinion or a combo of all? There are loads of ICK related research articles, and none of the few that I read made mention of the definition of "immunity" to ICK.
I can feel it in my bones, these ich threads always go bad.
After saying that I will say that these are my observations from having fish over fifty years and saltwater fish for forty years and spending almost 300 hours underwater. I write my own material and do my own research and come to my own conclusions.
So this is only my opinion, I do know what is written about ich because I remember when all the authors started writing about it.
I personally do not quarantine. Unless you have my tank, you should quarantine. There is ich in my tank and it has always been there just as it is on every fish in the sea.
Most of the time in tanks it will become epidemic and kill everything in the tank. I say most of the time because most tanks are not that healthy or old enough to overcome it. I really can't say why my fish don't die from ich but the first 10 years or so they died all the time.
It would do me no good to quarantine as I add all sorts of stuff from the sea including, mud, water, bacteria as well as fish, crabs, amenones, rocks and anything else I find interesting.
My tank will be 40 years old next year and I believe it is very healthy even though once in a while I will see a spot or two. This is normal and in "my" tank, no problem. There have been fish live over 18 years in there with the ich as most of them live long enough to die of old age.
If your fish are not spawning every few weeks, they are not healthy, sorry. If there is only one of a kind and no pair then they should at least be exhibiting spawning behavior like cleaning a nest or chasing away males. This is not all fish but most bottom dwelling fish. Damsels including clowns, and gobi's should at least show this behavior. If a fish is spawning that is the healthiest a fish could be and I have yet to see a fish in that condition with ich.
If I put a fish in my tank that has obvious ich (don't even think of doing this) it will ether die or become cured but never once in decades will another fish get ich. If I put in a healthy looking fish it will almost surely develop ich in a day or two but it always subsides in a couple of days and I have not lost a fish like this in many years. I buy a lot of smaller clown gobies (their lifespan is only a few years) and they sometimes become covered in ich and I am sure they will die. But for some reason, it does not happen.
Again, unless your tank is 10-20 years old and you know this is happening, I would quarantine.
Also if your fish are not showing spawning behavior I would correct the problem which could be a number of things including food. Feeding the same frozen food every day, no matter how good it is supposed to be does not cut it.
So this is my experience and I know many people have a lot of trouble with this paracite as I once did.
Have fun and don't do what I do.
Paul :smokin:
But I think I am in a similar situation. Almost every fish I introduce comes down with ich. In a couple weeks it has seemed to go away. Every once in a while I will see a spot or 2 on my hippo tang. All I can say is do what you want to do. This is a hobby we should be enjoying. Make sure you enjoy it and if you want to QT then do it.
