Nutrafin Cycle Biological Aquarium Supplement, 1-Ounce Biological aquarium supplement features a high-concentration formula that immediately establishes a safe biological aquarium environment Cycle goes to work fast, releasing massive amounts of beneficial bacteria that eliminate toxic ammonia and nitrites It is also ideal for quickly establishing safe and essential conditions in new aquarium setups, so that you can introduce fish to new aquariums immediately Available in 1 ounce plastic container Measures 1-1/3-inch length by 1-1/3-inch width by 2-4/5-inch height