With Fritz FritzZyme 9 Freshwater Aquarium Water Treatment, itâs easy to reduce the ammonia and nitrite in your aquarium. This saltwater treatment contains strains of live nitrifying bacteria that create a healthy tank environment. It can help to ensure these bacteria are ready to go when you build a new tank, so that ammonia and nitrite donât get out of control. This treatment greatly reduces the time it would take this good bacteria to take hold, so you can safely and immediately introduce your aquatic pets to your new tank.