Fungus is a very serious illness and if spotted on your betta it is important that you begin treatment right away. Fungus, if left untreated, can very quickly take over your betta with the end result being death. The sooner you begin treatment the better your bettas chances of survival.
Bettas are most susceptible to fungus attacks when the mucus slime coating (stress coat) on the skin of betta has been worn down because of stress due to poor water conditions, injuries, or damage by parasites.
Symptoms: White growths on the body and/or fins that are fluffy/fuzzy in appearance. May appear as long strands looking similar to fine hairs pulled from a cotton ball. May appear as small patches of short white fuzz. Symptoms matching the above would be signs of fungus types caused by bacteria.
Recommended Treatment: Jungle Fungus Eliminator
Jungle Fungus Eliminator comes in the form of yellow crystals, and the dosage breakdown would be (per Jungle Laboratories) 1/4 teaspoon per gallon of water. Also, adding aquarium salt, (not table salt) would aid in his healing as well as provide added protection. The dosage during treatment would be 1 teaspoon per gallon.
A more severe type of Fungus is one known as “True” Fungus.
Symptoms: Patches on skin of fish smooth or slimy in appearance. These patches may be white, gray or milky and would be flush with the skin. Blood and raw flesh may appear around the outside. As the illness progresses, portions of the bettas skin will dissolve away.