I’m not sure why you would want to. There is no reason to simply add garlic to any aquarium. Garlic added to food has shown to act as an enticing ingredient. However I believe it should only be use when you first get a new fish, and the fish is a picky one. Once the fish is eating I don’t see a reason to continue the garlic additive. If you believe that garlic acts as an immune system booster, I believe science has not yet backed this claim.