This disease is not caused by a pathogen, but by gases that are released in the water or the fish's body. Gas bubbles recognisably collect under the skin, in the fins and in the eye. If the lateral line organ or the brain of the fish is affected, the fish becomes disoriented and begins with tumbling movements. This disease often occurs after drastic water changes or after the initial setup. In these cases, the overall gas concentration of the water has still not attained its proper level. The water is oversaturated with gas and needs to calm first. Rapid warming in the aquarium leads to a kind of diver's disease in the fish. Aeration with bubble stones or a splashing pump can produce relief and restore a normal gas situation.