Garlic additives have been in use as a fish food supplement for several years now. It has long been known/thought that garlic boosts fish immunity and entices finicky fish into eating, but it also has a funny way of causing some corals to swell up and behave differently than normal. This especially holds true for fleshy corals, or at least it is more noticeable in these corals as they have far more tissue that inflates. The garlic may cause the corals to exhibit a more intense feeding response, which is what happens with fish, and it doesn’t seem to negatively affect the corals in any way from my experience. Unfortunately though, the sight of corals swelling to many times their normal size and acting differently may alarm many hobbyists, who might immediately ditch the food additive despite its many proven benefits.