API® STRESS ZYME bacterial cleaner contains over 300 million live bacteria per teaspoonful. It helps keep the aquarium clean and improves the natural aquarium cycle; as it consumes sludge and reduces aquarium maintenance. Making STRESS ZYME bacterial cleaner part of your tank’s regular upkeep routine assures an active biological filter, a cleaner aquarium, healthier fish, and good water quality. This product may be used in both fresh and saltwater aquariums.