Keep your tank healthy and thriving with the Fritz Aquatics Fritz Zyme 7 Freshwater Nitrifying Bacteria for Aquariums. It contains specific strains of natural bacteria that go to work to remove toxic ammonia and nitrite immediately in freshwater tanks, with no wait time. The bacteria in this formula quickly seed your biofilters so you can use it on new tanks and established tanks, especially after cleaning or medicating, water changes, or when adding new fish. Plus, it’s safe to use around invertebrates, including shrimp and other antenna-wearing pals.