I don't want to ruffle too many feathers but there is little scientific truth behind the use of garlic. The only evidence I have seen comes from those selling it as the cure all. Be wary! You might be confused as to the other supplement, there are two, one is Kent Zoe and the other is American Marine Selcon. Selcon is one of the best additives but is a bit pricey, Zoe is what I use on my tanks and for my sharks. One other suggestion is to feed a wide variety of foods as sort of a shotgun approach