API Marine Melafix is a safe, natural fish remedy that should be used to treat bacterial infections in saltwater fish and corals. API Marine Melafix contains Melaleuca (tea tree) extract to soothe and calm your fish, and rapidly repairs various fish ailments, from open sores to Popeye. It also reverses coral degradation. API Marine Melafix will not harm the biological filter in your aquarium and can safely be used in all marine and reef aquariums.