Hole in the Head Disease, or HITH, is a form of lateral line erosion disease. Normally healthy Oscars have a number of small holes around the area of the eyes, and along the lateral line. These holes become more pronounced as the oscar ages. They are perfectly normal, and should not be confused with HITH. Normal Sensory Pits:
HITH starts out as small erosions in and around the sensory pits. These erosions appear as small grey-white patches in the area of the head above the eyes.
If the area becomes infected, the areas may develop red streaks and puss may be present in and around the sores.
This condition is caused by poor water quality and/or poor nutrition. It can be easily cured, particularly if caught in its early stages by increasing tank maintenance to improve water quality, making sure the oscars are fed a balanced diet, and by dosing the food with multivitamins (Boyd’s VitaChem is a common recommendation). Pellets should not be soaked in advance as this will degrade the quality of the pellet. Pellets should only be soaked for a few minutes prior to feeding. An alternative and perhaps more effective method of vitamin dosing is discussed here.
It is imperitive that nitrate be maintained below 20ppm, with under 10ppm preferred for the duration of treatment. This will require frequent and large water changes.
While parasites such as Hexamita may be present in the sores, they are there on an opportunistic basis, and are not the cause of the condition. If your Oscar shows symptoms of parisitic infection, that infection should be treated by apropriate means.