Clear-Water Barley Straw naturally decays in your pond water, releasing enzymes that aid in maintaining water clarity. A safe natural pond treatment to improve water quality which provides a healthier environment for Koi and other fish. The breakdown of these natural pollutants acts to cloud the pond's water. Keep your pond water clean and clear year-round! Clear-Water Barley Straw products are easy to use, safe and attractive. Clear your pond, fountain and fish tank naturally!