API Pond Algaefix effectively controls green water algae blooms, string or hair algae (Cladophora), and blanketweed (Oedogonium) in ponds containing live plants and fish. This algae control is fast-acting, controls algae growth, controls the formation of new algae, and helps resolve algae problems. Registered with the EPA, this product controls many types of algae in water gardens, ponds, and ornamental fountains containing live plants and fish.