The cotton-like growth/tuft is generally an actual fungus (Saprolegnia) (Ill. 107-114), but in some cases the symptoms may have been caused by parasites, Stalked Ciliates (Ill. 115+116) These symptoms usually occur after damage or after infections caused by parasites or bacteria. See also WHITE PATCHES ON THE SKIN: - Ill. 35: Oranda with a white head caused by fungus following a bacterial infection? - or Ill. 34: Guppy with a white head caused by the Tetrahymena parasite. See also SPOTS, Ill. 99 White fin edges on Scatophagus caused by a virus (Lymphocystis). The latter is easily mistaken for fungal infection. Tip: Whitish cotton-like growths on the skin or fins are not always fungal infections.