Maracyn Oxy successfully controls fungus infections caused by Saprolegnia, Icthyosporidium, egg fungus and related species, and common bacterial infections. It slowly releases small amounts of a stabilized oxygen-chlorine combination which, when used as directed, has an unusual ability to treat a wide variety of tropical fish diseases. Fungus infections are usually found at the site of an injury or recent attack from parasites. A true fungus infection has a cotton-like appearance similar to a mold found on fruit, bread or cheese, except that on a fish a fungus is usually white. Fungus infections are very difficult to treat and are usually secondary invaders resulting from an injury on the fish or recent wounds from parasites or bacterial infection. Once the fungus starts growing on the fish, it usually continues to grow and enlarge. Unless medication is provided, death results.