Harness the power of nature to reduce aquarium nitrate and phosphate levels. Two Little Fishies NPX Bioplastics is a biopolymer filter media that helps maintain aquarium water quality by supporting the growth of nitrate and phosphate reducing bacteria,These bacteria can be harvested by protein skimmers, so that the nitrate and phosphate levels are naturally reduced. The bacteria are also a food source for filter-feeding invertebrates such as corals, clams, sponges, and feather dusters. Use with Bactiv8 NPX to promote rapid assimilation of nitrate in saltwater aquariums