Sea Chem GarlicGuard is an appetite/flavor enhancer for freshwater and saltwater fish. GarlicGuard will help renew the interest of poor or finicky eaters. GarlicGuard contains the naturally derived, active ingredient found in garlic, allicin, which has been demonstrated to possess health promoting benefits. Allicin possesses strong anti-oxidant properties (similar to Vitamin C) which promote enhanced health through elimination of dangerous free radicals. For enhanced health benefits, SeaChem GarlicGuard also contains Vitamin C. Freshwater and Marine. Reef safe. Seachem Garlic Guard - Fish Supplements