Features - For Freshwater Aquarium & Pond Use - Absorbs Toxic Ammonia That Is Lethal To Fish - Polish Water For Improved Clarity - 10" x 18" - Cut-To-Size Tideline Filter Pads are a great way to keep your aquarium clean and your fish healthy! With numerous mechanical and chemical filtration pads available, you can choose the filter pad or combination of filter pads that suit the needs of your aquarium. Tideline Filter Pads feature a thick and rigid design that allows you to cut them to fit any hang-on, canister, internal, wet/dry and pond filters. Tideline Filter Pads are versatile and effective tools for any aquarium hobbyist or professional. * box quantity discounts sold in full boxes of 36 filter pads.