Dropsy fish is a condition that is often caused by a bacterial infection in the tissues of the aquarium fish due to poor water quality. The primary issue is the accumulation of fluid in the tissues due to excessive water intake or inadequate elimination of water from the system. Although it is not a disease, yet for technical reasons, most experts address it like an illness. It is imperative to understand that although there is a chance that fish may recover spontaneously with treatment, it is highly suggested to keep the dropsy fish separating from normal fish to prevent the spread of illness.

Symptoms of Dropsy Fish

Symptoms fluctuate between two extremes, i.e. some fish present only with skin lesions while others develop classic pot belly appearance. Due to high disparity and overlap of symptoms, it usually becomes hard to diagnose this infection with precision. In most cases, the symptoms are progressive and begin to appear as the infection spreads. Primary internal organs that are affected include kidney and liver. In addition, gills are also involved.

Common symptoms of dropsy fish are:

  • Heavy tummy that appears swollen and bloated

  • Ulcers along the lateral margins of the body

  • Gills turns pale (due to anemia)

  • Stringy and pale feces

  • Bulging of eyes

  • Swollen and red anus

  • Scales stand out (more like a pinecone appearance)

  • Fish spine lose its strength and stability

  • Changes in the eating behavior

  • Swim or float near the surface of tank

  • Lose energy and appear lethargic

Causes and Risk Factors of Dropsy Fish


This infection is caused by the bacteria Aeromonas. This bacterium is normally found in aquarium due to bad quality water. The most prone fish are those who are under stress or have poor or weak immune system. Likewise, in cases of systemic involvement (for example kidneys), the fish tends to accumulate water that makes the belly swollen and bloated. In many cases dropsy is not fatal, but it is more preferable to seek treatment for early symptoms.

Risk Factors

The most important factor that leads to dropsy in fish is stress. Getting stressed for short time does not cause dropsy but long-term exposure can increase the risk. Another important risk factor is poor or compromised immune system. There are certain other factors that may contribute to aggravated levels of stress in the aquarium fish.

  • Bullying from other tank mates

  • Presence of a disease or parasite in the aquarium

  • Poor quality diet or insufficient food

  • Inadequate survival conditions for certain fish

  • Sudden changes in water (in terms of temperature and pH)

  • Injuries incurred as a result of bullying by other fish

Treatment for Dropsy Fish

If you come across dropsy in any of your aquarium fish, it is highly recommended to take following actions for the management.

Isolate the Sick Fish in Quarantine Tank

Clean the original tank immediately and keep an eye on the sick fish. Treat the sick fish in cleaner and healthier environment.

Addition of Salt

Insert Epsom salt about no more than 2 and half teaspoons in the quarantine tank. Since Epsom salt has a property of extracting extra water out of belly, it should improve the overall health of the ill fish.

Antibacterial Diet

Buy an antibacterial diet or prepare one by yourself. All you need is a mixture of antibiotic such as tetracycline or chloromycetin with fish food. And keep this diet running for at least 10 days. Make sure to keep a strict check on the fish behavior during that time.

Use of Antibiotics

If antibacterial diet and salt are ineffective in 10 to 15 days, the last option is to use antibiotic in the tank water. Add Maracyn Two in water of the tank. This will kill the bacteria that are present in water and since it is easily diffusible through skin, it usually exerts its action in a few days. But remember to see the dosage and other instructions on the label.

However, if the antibiotic treatment also fails, there are very few chances that the fish will survive because dropsy is probably not caused by the bacterial infection. In such conditions one should contact the nearest pet store or hospital and seek guidance from professionals.

See the video below to learn more about the treatments for dropsy fish:

Prevention of Dropsy Fish

Prevention is far better than cure. So there are many preventive measures that should be taken so that no fish is harmed by this condition. All we need to do is to find out what factors are causing stress in fish and then eliminate those factors.

Keep the Aquarium Clean

  • Change the tank water regularly: the water should be changed every week and the whole tank should be cleaned at least once in a month.

  • Change filter: filter is perhaps the most essential component of an aquarium and it should be cleaned at intervals to maintain the filtration activity.


Avoid Overpopulating Your Tank

Make sure that there is ample space for every fish to move individually without any problem. This is an important element in the prevention of stress.


Don’t Give Surplus Amounts of Food

Extra food that is not consumed settles down in the bottom of the tank and decompose, thereby increasing the risk of bacterial diseases due to food decay.


Variety of Feeds/Nutrients

Feed the fish with a wide variety of foods. Make sure to use the flake food within a month of opening the pack.


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