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Common Goldfish Diseases, Causes, Treatment, and Prevention

If you raise your goldfish in a well-kept goldfish aquarium, feed them well, and prevent stress factors, then expect your pet fish to live up to their full life expectancy of 15-20 years. But since you have other work to do besides maintaining the goldfish aquarium, it’s not uncommon to forget checking some aquarium parameters like electrolytes, temperature, pH, etc. That’s how common goldfish diseases creeps up and attacks your aquarium fish. Because of that, you have to at least know the common goldfish diseases, causes, treatment, and prevention.

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Ich or Ick Goldfish Disease

Ich or ick goldfish disease is characterized by the appearance of white spots on a goldfish’s scales, fins, or gills. If not treated, it could kill all the fish in the tank. Ich is caused by stress, fluctuating tank temperature, and mishandling of the pet fish. Some overly sensitive goldfish species even develop ich due to stress after being transferred to a new tank.

Adding aquarium salt and anti-parasitic medication to the goldfish aquarium water should cure goldfish ich. To prevent the disease from showing up, insure that the water parameters are correct and that the fish are free from stress.


Although constipation is more of a physiological condition than a disease, it’s included in the list because of its effect on the goldfish. Constipation, which shows as feces trailing behind, can stress the fish that in turn cause other diseases.

Constipation is caused by lack of variety or too much starch in the diet. So the remedy should be to provide more variety by giving your fish chopped spinach, peas, and live feeds. Feeding 1 grain epsom salt to the constipated goldfish should take care of the problem also.

Tail or Fin Rot Disease

Tail and fin rot, which appear as necrotic lesions on a goldfish’s tail and fin, are caused by bacteria or fungal infection and stress. Too high ammonia, nitrates, and pH in a goldfish aquarium can chemically erode a goldfish’s tail and fin too. The treatment and prevention of tail and fin rot involves the elimination of the causes.


Dropsy is a deadly fish disease, which goldfish are unfortunately particularly susceptible. It’s characterized by distended belly, swollen eyes, and scales sticking out like open pine cone scales. The worse thing about dropsy goldfish disease is that it’s often too late when the symptoms appear. That’s why it’s all the more important to prevent the disease from showing up by keeping the goldfish aquarium clean. Changing 25% of the water weekly is said to help prevent the disease.

Swim Bladder Disorder

Swim bladder disorder is characterized by goldfish floating on its side on the surface or having trouble keeping right side up in the water. It’s caused by bacterial infection, improper diet, or trapped gas in the intestine. If bacteria caused the disorder, an antibacterial treatment should take care of the problem. If trapped air caused the problem, it can be prevented by feeding goldfish with sinking or presoaked feeds.

Cloudy Eye Disease

Cloudy eye goldfish disease is characterized by cloudy to opaque appearance and mucus on the fish’s eye. The usual cause of cloudy eye disease is dirty water full of ammonia and nitrates; thus, keeping the goldfish aquarium water clean should keep the disease at bay. Other causes of cloudy eye include vitamin deficiency, eye parasites, bacterial infection, and ich.


Goldfish ulcers are caused by microscopic organism Pseudomonas and Aeromonas found in dirty water or brought by live feeds. The ulcer appears as pinkish to red lesion with white edge and is painful to your pet fish. Treatment of goldfish ulcers includes 1-3 grams salt/litre of water and some goldfish aquarium antibacterial medications. But like any other goldfish disease, prevention is better than cure. So keep the aquarium water clean and minimize feeding live feeds to your goldfish.

Fungus Disease

Fungus goldfish disease appears as cottony, fluffy white growths on a goldfish’s skin. It usually appears secondary to wounds or other infections. Treatment includes methylene blue, aquarium salt, and in rare occasions antibacterial medications. Fungus disease, however, is easily preventable if the water aquarium is kept clean.

Knowing these common disease, their treatment, and prevention should help you take care of your pet goldfish. There’s no reason you can’t see your goldfish live its full life if you only take good care of it.

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