OK, You have me convinced that the fish has small parts of ich on it during times of its life cycle. It would make no sense for it somehow to magically stay alive without its host fish. Now who do you know that has not added ANYTHING to their tank in a year? Most everyone adds things to their tank like snails and corals without treating for ich. So it is possible, but also improbable to have a tank free of ich.
Correct. Possible, but who's not gonna have any fun and add more stuff.
Could you explain how ich somehow dies off after a year? Is it not "fully" infecting the fish so it does not get enough of whatever it needs to live?
I have absolutely no idea. I'm trying to find the article I read (I thought it was from Reefkeeping.com but I may be wrong about that) about it.
If 99% of the reefing community do not QT everything that goes in their tank and add multiple things a year, then it clearly is connected to immune system. These fish are just fine how they are, why be so concerned about ich then?
I think it's less immune system and more tolerance and a healthy slime coat. Stressed fish have little slime coat and the parasite is allowed to attach to the body, hence the white spots.
Are you saying that once the white spots appear it has gone too far? I have had fish get the white spots and the fish kicks the parasite and life goes back to how it was. I have heard the same from many reefers. Why then, do you think that your suggested treatment must take place for a fish that has white spots?
In a lot of cases, yes. By that point, the fish can't keep up and the parasite takes over (Ich is a crappy parasite, ya know? Most good parasites don't harm the host too much to keep them alive so they can keep preying on them. Seems counterintuitive to be able to kill your host!). If the fish are conditioned and the aquarist has good husbandry, they have a higher chance of fighting it off, but again, by the time the spots are there, the fish is weaker than before and is easily overtaken by more parasites.
And just because the white spots are gone does
not mean they beat the parasite - it has simply taken back to infecting the gills, which are not protected by the slime coat and are easily accessible.
So what do you suggest happens after your QT period? Do you never add anything to your tank again?
What's the fun in that?
Just saying that it is 100% possible to have a tank that is not carrying ich.
That made me LOL. Sorry, I got a bit carried away with the structure of logic. (you usually wrap up an if/then with a conclusion taken from the first and last statements.

)
LOL
Proof of what? It is a given that garlic has the properties and contains the ingredients that I listed. The garlic has the vitamins, the fish eats it, the fish gets the vitamins, the vitamins help the fish's immune system. What else is there to debate?
Whether or not it actually helps, and that is what that article covers. Manufacturers have claimed for a very, very long time that garlic has all these benefits, including outright curing
Crypto outbreaks, which it simply cannot do, ever. 100% impossible.
Yes, and they can benefit even more from supplements. Why not go above and beyond to make your fish healthy?
Only so much can be done. A varied diet will provide nearly and up to 100% of what the fish needs, anything else would possibly be wasted and passed through, as the fish would not need it at that time.
The first link is long gone. The second is a study done on a freshwater catfish. Catfish are not even related to the fish we are discussing and who knows how a marine fish would react to the same test.
The post goes on to say "When I first started in the hobby I had 2 fish come down with severe ich and I didn't feed garlic and the ich went away. Since then I've never fed garlic and never had ich either. It's well documented that fish can recover from ich and develop immunity with no treatment at all. In the absence of controlled tests showing that orally administered garlic is effective, there's no way to attribute the effects to garlic rather than just the natural ability of the fish to fight the parasite."
I don't have anything to back up garlic and you have no evidence of it being detrimental. I know that many people feed garlic to their fish and the fish are fine.
The first link I can't find a copy of, even Archive.org doesn't have it. :/
That wasn't the important post.
Clearly there is evidence that in high doses garlic can damage the liver of fishes. However, I don't know of any studies that looked at the histopathology of using smaller doses, so there's really no way to say what, if any, dose is safe.
There haven't been any studies done showing that orally administered garlic does anything to fight off protozoans in fish. All we have to go on is anecdotal evidence from people saying that they fed garlic and the ich went away in 3 days or that they've fed garlic and they've never had ich. The trouble with that is that people who don't treat with garlic or treat with "cures" that are known to be ineffective can say the same thing. When I first started in the hobby I had 2 fish come down with severe ich and I didn't feed garlic and the ich went away. Since then I've never fed garlic and never had ich either. It's well documented that fish can recover from ich and develop immunity with no treatment at all. In the absence of controlled tests showing that orally administered garlic is effective, there's no way to attribute the effects to garlic rather than just the natural ability of the fish to fight the parasite.
Also, there's evidence that although garlic may induce fish to eat more, it induces lots of metabolic changes that cause the fish to use the food less efficiently. So again, there shouldn't be an assumption that because the fish eat more with garlic, they're healthier.
While I don't think there is enough evidence to say one way or the other whether feeding garlic is directly harmful to fish, I do think it can be dangerous in the sense that people choose to forgo proven treatments in favor of garlic which is untested. Ich is afterall a life-threatening disease.
That's more along the lines of what I was getting at, you'll fine people saying that
anything they did 'cured' ich. I'm in the camp that garlic should
not be a regular addition to a fish's food, and should only be used as an appetite stimulant in training a picky fish, or when trying new foods to get the fish to recognize it as such.