Clear ponds inconspicuously with these natural-looking planters. Constructed of barley straw. Showcase beautiful plants with no danger of koi nibbling. Safe for Fish & Plants. Improve your water quality with this attractive, floating planter. Barley Straw Planters act as a natural filter, keeping the water in your pond clean and clear, fashioned into a showcase for houseplants or other non submersible species. Won't harm fish or plants, and treats pond for 6 months. Treats 2500-4000 Gallons - Large 8 x 11 x 11 inch