API AlgaeFix controls the main and most persistent types of algae in freshwater aquariums, and does so without causing harm to your fish or plants. You can use AlgaeFix as part of your aquarium maintenance routine, or to directly treat and control algae. Weekly doses of AlgaeFix will control algal growth and reduce aquarium maintenance over time. Do not use with freshwater crustaceans, including shrimp, crabs, and lobsters. API Marine Algaefix controls many types of algae growth in marine (saltwater) and reef aquariums, including Green algae, “Red Slime,” and “Brown Algae” in aquariums containing live corals, invertebrates, and fish, and does not discolor water or cause foaming. API Marine AlgaeFix should be used weekly to control algae growth, as part of regular care to reduce aquarium maintenance. API Marine AlgaeFix is an EPA registered product, and will not harm any live element of your saltwater or reef aquarium.