Excessive algae growth is the most common complaint of aquarium keepers of all experience levels. Left unchecked, it is both unattractive and hazardous to fish and plant life. Fritz Algae Clean Out is the most concentrated EPA-registered algaecide formula available. Fritz 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.