For this product we require a completed Drug & Chemical Affidavit on file. If you have not submitted this form to us, please click here, and fax (813-671-8237) or email (fishsupplies@verizon.net) back to us. Thank You. Contains two furan compounds to combat a wide variety of gram-positive & gram-negative bacterial diseases, including bacterial gill disease, open red sores (Aeromonas spp.), body slime & eye cloud, black molly disease (Flavobacterium columnaris) and fin & tail rot. For use in both freshwater and saltwater aquariums. This medication will not harm the biological filter. Note: This medication will cause a slight discoloration of water which can be removed with activated carbon. info from Aquarium Pharmaceuticals.