I posted this someplace else. I think on the White House wall near the bathroom on the first floor.
I take probiotics myself but there is no need to give them to "my" fish or anyone's fish that are fed correctly. It's like vitamins and minerals. If those things have to be added to food like you see in the ingredients of dry foods, freeze dried foods and white bread, it is because those natural things were removed from the original foods because it is either cheaper to do that and add them later or the drying process eliminated those things so after processing those things are artificially added later to make the product seem better. And sometimes they are. But foods with those things naturally in there are best.
White bread is interesting because you will notice that it is always "enhanced" with vitamins and minerals. Look on a package of it. The makers of white bread don't add those things because they want to make you healthy. They add them or they would not be able to sell it as food because white flour has no nutrition and can not be called food. Whole wheat flour is fairly nutritious but whole wheat requires refrigeration which is expensive so they remove everything including the wheat germ and the bran and what you are left with is starch which is good for making glue but it won't keep anything alive. Even bugs don't eat it, guess why?
But white flour needs no refrigeration so it will last forever and can be stored in the same place they store Oldsmobile parts or tennis rackets.
Pro Biotics are great but they won't get your fish immune because Probiotics are good bacteria that help with digestion. They are not designed to do anything else and if we ate like we were designed to, we would not need them either. We are basically hunter gatherers who are supposed to eat a little bit of almost anything many times a day, including insects. I don't much like bugs and my wife frowns on gathering so we "hunt" in a supermarket like most people. Supermarket stuff is fine, but much of that stuff is processed so we no longer get a lot of dirt in our diet. Animals, including fish get a bit of dirt in their diet and some animals like grazers such as horses, cows and manatees get a lot of dirt in their diet. They don't care. Elephants even eat clay dirt for their well being.
We aquarists think that is a terrible thought and wouldn't think of putting dirt in our tanks or feeding our fish food that is not hermetically sealed. pasteurized, sterilized, UV Radiated and put in a nice package with a beautiful angelfish on the front.
It's the lack of "dirt" as well as the lack of bad bacteria and parasites that is the reason for all the disease threads, not the other way around. The natural diet for almost all fish is live fish. All fish have a gut and that gut is filled with whatever their last meal was which was another fish along with the parasites and disease causing organisms that go along with it. If we eliminate that diet of disease causing pathogens we also eliminate any chance that the fishes immune system will recognize those things so we must keep fish away from those things which also means we have to keep them away from their normal, natural diet that contains disease organisms.
I don't feed anything sterile so my fish have the same immunity that they had all their life which is the reason I never had to post on a disease forum. There has never been a disease in my tank since probably the late 70s or 80s and none of my fish have ever been sick and they never will.
Only quarantined fish or fish not on what I consider a correct diet which is natural food like they get in the sea with all the diseases that are naturally in the sea.
I feed live blackworms and whiteworms as well as clams. The whiteworms live in soil and it is sometimes difficult to seperate them from the soil so I add the soil right along with the worms. That soil is loaded with bacteria.
I also add mud from a muddy harbor or my back yard. These are things many of the people posting on the disease forum would never do and that is why their fish are sick.
This "out of the box" thinking does not make me a lot of friends but I already have plenty of friends. One less since Soupy Sales died.