Also, I think Paul is significantly underestimating the impact of his reverse flow UG filter.Studies have shown that many parasites and pathogens wait in the substrate waiting for a new host. I believe that the passive current from that contributes to them not being able to stay there, thus allowing for a far less density of pathogens, which will be less taxing on his fish's immune system.
I think this may be a stretch, but what do I know. I love my reverse undergravel filter and if it annoys parasites, so be it. I also have been using ozone ever since my tank started. I built my first ozone generator from a neon transformer but it was so powerful that it tended to dim the lights in the neighborhood so I ended up buying one. If that has any impact on parasites, you would have to ask the parasites. My tank is also full of sponges that "probably" eat parasites for lunch. But I have only had them for 10 years or so, so they would not have an impact on my fishes immunity.
As was said, this thread has gotten way off subject. I did say, If you want to quarantine, go for it. I am merely trying to elicit a discussion on a different method. A different method that I can prove works. It's not for everyone and there are many people on this forum that won't even come on this thread to read it because if you mention to some people that there is an alternative to quarantining, they get upset. That is "one" reason I don't go on "that" forum any more. Some people are just not into a different idea and that's fine. There are plenty of threads I don't go on because I disagree with the author and feel I would just screw up their thread.
There are plenty of quarantine threads I don't go on because I feel I would be a detriment as I don't use that system because "In my mind" I found a better way. I could of course be totally wrong, but that is in my mind and since it has worked for decades, why change now. I also don't go on a thread that reads "Which are the best dry foods" because I have nothing to say about them.
I don't go on threads that state that my fish has a spot, what should I do, and the advice is to remove all the fish for 72 days and treat with Prozapro, sulfuric acid, Metrothiolate something etc. Then the fish dies.
I don't think fish are so delicate. If my salinity is a little low, I add some salt water, not over a month, maybe over an hour. I don't acclimate for a day, I acclimate for maybe 20 minutes and have never lost a fish acclimating.
For some reason I don't seem to have the problems many people have and I never have any of the fish disease problems, could I be that lucky?
I try to explain my methods that took me fifty years to learn but it is hard because of the arguments. Not on this forum of course.

I don't know what it is but I have been trying to explain it. I get up, feel the glass of my tank to check the temperature and go about my day. At night I feed them and go to bed. That is 95% of my maintenance. If a fish dies, it will always be from either jumping out or old age, then I will autopsy it (if I have time). I know most people find a dead fish and just flush it, then they guess all the things it died from. If I am in a hurry I will at least examine the gill filaments. Anyone could and should do this. Use a magnifying glass or a cheap jeweler's loupe and look for torn tissues or parasites. They are very easy to see. I mentioned this once and I was immediately yelled at because it was too complicated and we are not doctors. How stupid are we? If we get a splinter do we go to a surgeon to remove it? The fish is already dead! He won't sue you.
If you find torn gill filaments or parasites you will know that you have a problem and need to address it.
I wrote that I cure Pop Eye with a hypodermic needle in 5 seconds and got the same response. I am an electrician and I have no problem doing it. If we were the only two people in the world and your eye was hanging out of your head and I said I could cure you in five seconds would you say, Oh God No, I like seeing behind me and on top of my head at the same time.

Or would you say, what are you waiting for.
This is not rocket science and we are dealing with Fish, or what I usually call, lunch.

I look very immune here.
