‘Hole in the head disease’
Cavities start to develop, particularly on the head of the fish, small at first then increasingly bigger. In many cases, a whitish, pimple-like coating becomes apparent. Fish look as though the tissue around the head is eroding away.
The exact cause of ‘hole in the head disease’ is far from clear, but a group of single-celled intestinal parasites, e.g. Hexamita
, are thought to be at least partly responsible. Bacteria and potentially a lack of minerals or nutrients could also be the cause of the "hole in the head disease". Incorrect water values or food also play a key role in the development of the disease.
Affected fish should be fed a diet that is as varied and nutrient-rich as possible (only use top-quality brand foods). Make sure to offer your fish a stress-free environment and ideal water values. For cichlids in particular, social stress due to combining incompatible fish species often causes the disease. The single-celled intestinal parasites can be treated with suitable medicines from pet stores.