Cloudy Eyes-

There are two main types of fungus. The "True Fungus" and the "False Fungus".

The false fungus is called Mouth Fungus, Mouth Rot, or Columnaris Disease. While this disease shows all the signs of being a fungus it is actually a bacterial infection.

Signs

Chronic form:
Small, off-white to grey, marks on the head, but sometimes on the fins and gills. The lips are most likely to be infected, and the inside of the mouth.
The initial lesions develop into off-white fluffy growths resembling cotton wool, hence the confusion with true fungal infection. Mouth fungus has however a coarser and more granular appearance, and is often greyer in colour than true fungus.
Acute Form:
A systemic infection, usually occurring at tropical temperatures, with an incubation period of a few days. Fish do not always show external symptoms but may die in just a few days. Diagnosis is normally only possible on a post-mortem examination. This disease may be responsible for some unexplained deaths.
Cause - Flexibacter Columnaris

Transmission
The bacterium is commonly present in aquariums water, on dead organic material, or even on healthy fish skin, and may invade damaged or unhealthy skin and the surrounding tissues. The bacterium appears to be more pathogenic under hard water conditions with a pH above 6.

Prevention
Good husbandry. Don't keep fish under the wrong conditions, i.e. Fish from hard or alkaline waters in soft acid water.
Monitor your aquarium for correct pH, Nitrite, Nitrate, and Ammonia levels. Ill health due to incorrect environment is far more likely than than flexibacter infection.

Treatment
Bath immersion using a treatment containing Phenoxyethanol is normally effective. It is also fungicidal and will cater for misdiagnosis in case of true fungal infection.

The true fungus or cotton wool disease.

Signs
Fluffy, usually white or whiteish growths, and usually at the site of an injury or where the skin has been damaged by disease, including wounds left by large parasites or by fighting. Untreated fungal growths may turn grey to reddish-brown with time, as they accumulate dirt and algae. The untreated areas will soon spread to healthy tissue which will eventually lead to death. Fungus is often seen as a secondary infection to diseases like fin rot.

Cause
A number of different types of fungus including Saprolegnia are commonly blamed for all fungus and Achyla. Other fungi may be involved and a single site may be attacked by many species of fungi.

Transmission
Fungi are found in most aquariums feeding on dead and decaying plant and fish matter. In fact anywhere the water quality is poor.

Prevention
Good husbandry cannot be stresses enough. Stress, poor hygiene, chilling, injury, old age and other diseases will allow fungal infections to multiply.

Treatment
Do not dose the tank, if it is not really needed.

If only one or two fish are infected, a hospital tank is the better option. If all or most of the fish have fungus, you will have to treat the whole tank but this will be useless if you do not solve the underlying problem (see prevention).

The following options are available.

A prolonged salt bath has an effect on most fungi and is better for the fish and plants as long as they are salt resistant.

Add an aquarium fungicide, one containing Phenoxyethanol can be used.

If you have no room for a hospital tank and the fish is still fairly healthy you can apply the fungicide directly on the affected spot with a soft swab. This minimizes stress to the fish as it is returned to it's own tank straight away.

Don't Forget good hygiene, minimal stress and proper feeding should help give no problems of this nature.