I really appreciate all the great replies! Yes, IgA antibodies are what I was thinking about. Antibodies within the secretions of the fish for creating an immune response to the pathogen. From my studies, I've concluded that while it is a parasite it is also considered a pathogen. This has actually been achieved in groupers, sorry to shoot all the negative nancies down...
As for a cure for AIDS, yes, this has been achieved in two patients I believe (as far as they can tell so far). But the question becomes, "Is this type of treatment worth the cure vs. management?" For curing all types of cancers, I think that is a longshot. This is an easier thing to do than regulating growth mechanisms within a cell.
Nope, this would definitely not be an economical thing to do in the least, and you are right about having to purchase some type of health insurance for your tank, LOL- and that would possibly be the ultimate scam. So, perhaps, we are doomed either way.
This question was for a research proposal in my immunology class. My teacher said he really liked the report, and we talked about the subject for a little while. I was thinking of the Sabin vaccine as well, Sleepydoc. I really think its possible, but I'm not sure if an oral version would be feasible. One of the biggest issues would be culturing the organism, as that has yet to be done in a laboratory without live specimens to carry it.