Seapora Filter Floss is a dense mechanical filter media designed to remove fine/coarse particulate matter from your aquarium system. This process prevents obstructions in the biological media, thereby diminishing the risk of fish stress and disease. Also helps keep your aquarium water crystal clear! Seapora Filter Floss can be cut and shaped to fit any filtration system, such as: Canister Filters, Hang-On Filters, Trickle Filters, Pond Filters, Wet/Dry Filters, and other mechanical filter applications. Great for both freshwater and marine applications.