Here some information for you.
Fungal Infections
Symptoms:
Fungal infections can be differentiated from other infestations because white, gray or brown cotton-like growths can be seen on the fish.
Cause:
Healthy fish are not affected by fungi, but succumb following an injury to the skin. Fungal infections are caused by various species of Fungi, such as Saprolegnia and Achlya.
Treatment:
The most important thing to do is return water quality to optimal levels. Since fungal infections are not contagious to otherwise healthy fish, treating only the infected fish is recommended. Treatment should include dabbing the affected area with a cotton swab dipped in Methylene Blue. Use caution in the fish�s eye area because Methylene Blue can cause permanent damage if applied directly. If the eye is infected, or the fish is small, a dip is preferable. Prepare a bucket using fresh, dechlorinated water of the same temperature and pH as the water in the aquarium. Add one drop of Methylene Blue for each gallon of water and place the fish in it for ten to twenty minutes. Dips may be repeated up to two times a day until symptoms have subsided. If several fish are affected, treat the entire tank with Methylene Blue, Fungus Eliminator, Fungus Guard, or Fungus Cure.
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