Infections

• Goldfish swim bladder disease is usually caused by a parasitic or bacterial infection. Treating the underlying cause will usually resolve the problem if it is caught early enough.
  
  

Genetics

• Breeders sometimes unwittingly create a strain of goldfish with a genetic predisposition to swim bladder disease as they try to establish a certain trait, such as a particular color or tail shape.
  
  

Nutritional Factors

• Goldfish fed a diet lacking in proper nutrients are very susceptible to swim bladder disease, although if the diet is improved it will often recover. Also, a diet that leads to constipation can swell the abdomen to such an extent that the swim bladder cannot function.
  
  

Disease

• Cancer and tuberculosis can cause swim bladder problems if they attack organs near the swim bladder.
  
  

External Factors

• A rapid change in water temperature or blunt trauma sometimes caused by fighting can cause swim bladder disease.