There is no relationship between garlic's effect on bacterial infections and parasitic infestations. Also, the fish were not fed garlic-laced food; they were injected with garlic extract. That brings into question whether feeding fish garlic extract would be as effective as injecting them with it. Additionally, the garlic extract was prepared freshly for every injection. This is particularly important when taking into account the effectiveness of commercial preparation, and also in light of the fact that allicin, the active ingredient in garlic, is unstable and prone to breakdown in a relatively short amount of time (Cortes-Jorge 2000). Furthermore, since garlic is a non-natural food, the antigen effect of a novel compound may have been responsible for increased immune response, and although they used a negative control (nothing), they did not use a similar variable - i.e. onion, paprika, nutmeg, or whatever else one has in their spice cabinet that they think might somehow help their fish fight disease). And finally, even though all the fish showed improvement by the end of the study, none of the fish was completely healed. They all remained infected with Mycobacterium marinum, although at low levels.
. So who on here feeds their fish garlic? and What does it do?
/www.reefkeeping.com/issues/2005-10/sp/index.php
...so, I would like to apologize. I'll have to do some further research and try it myself 
