Cause of this disease is increase of water pH above 9-10. This can happen rapidly (immediate change a few mesh in scale) or over a longer time (pH change is gradual). In the first case the fish immediately begin to behave strangely and signalize worrying signs. In the second case symptoms of the disease appear after longer time or when we let in to aquarium new fish or we have old fish with weakened immune system. Other fish can adapt to some extent to new conditions. Symptoms of this disease often connect to symptoms of ammonia poisoning because ammonium ions change into toxic ammonia in alkaline water.
We need eliminate main cause of this disease when we its find. Next we need check all water parameters (especially pH, water hardness, nitrites, nitrates and ammonia) and we may do 30% partial water change (removal of fish isn't necessary) or we may change whole water (transfer fish to a separate aquarium is necessary). We need control water pH and other parameters after each the partial water change. We intensively saturate water with oxygen. The water for partial changes must have neutral pH =7. We should use adequate vitamin preparations and water treatment conditioners in order to strengthen fish immune system (e.g. Tetra AquaSafe, Sera Aquatan, JBL Atvitol, etc.). If we don't have high water alkalinity (temporary hardness) we may try to acidify the water with help of carbon dioxide or peat. When fish have damage their gills we should immediately commit an act of euthanasia these fish.