contains two furan compounds that fight a wide range of gram-positive and gram-negative bacterial diseases, such as fin and tail rot, body slime and eye cloud, open red sores (Aeromonas spp.), black molly disease (Flavobacterium columnaris), and bacterial gill disease. The biological filter will be damaged by this drug. Note: Activated carbon can be used to remove the slight discoloration that this medication will cause in water. for aquariums with both fresh and salt water. Up to 100 gallons can be treated (10 gallons per packet).