Help your finned friends breathe easily with the Aquascape Cold Water Beneficial Bacteria Liquid Fish Filter Media! This fast-acting biological booster contains seven pure strains of beneficial bacteria at 1.5 billion CFU per ounce. It’s formulated for use in very cold water， and it works quickly to balance your pond’s ecosystem. It also helps to control harmful ammonia， nitrite and excess phosphate. Keep your scaly sidekicks happy and healthy!