In short, no. My friend Ted is a fish disease research scientist and his lab has done several independent studies on the efficacy of garlic enriched fish foods. Here's what he had to say about the use of garlic on another forum. The results lead to my conclusion that garlic could potentially be used to entice fish as a last resort, but should not be used for anything past that.
As with most additives, save your money
As with most additives, save your money