Excessive algae growth is both unattractive and hazardous to fish and plant life. Fritz Algae Clean Out is the most concentrated EPA-registered algaecide formula available. Algae Clean Out targets string algae, blanketweed and green water caused by single-celled algae. Unlike some algaecides on the market, Fritz Algae Clean Out contains no copper and is a selective algae control product that will not harm fish and live plants when used as directed. Fritz Algae Clean Out is effective in both freshwater and saltwater aquariums, fountains and small ponds.