How to Cure Goldfish Dropsy

Co-authored by Craig Morton

Last Updated: August 23, 2024 Approved

Dropsy disease results when the kidneys fail to work properly causing fluid retention and swelling of the goldfish's belly. In late stages of dropsy disease, the scales of the goldfish will protrude outwards. When you observe these symptoms in a sick goldfish, its chances of survival are low. If dropsy disease is diagnosed early, goldfish can survive. By correctly diagnosing dropsy and treating the symptoms as well as the underlying disease, the goldfish will have the best chance of recovery.

Goldfish Dropsy Disease Treatment

Fill a second tank with fresh water at the same temp. as the original tank.
Gently place the fish inside the new tank.
Adjust the temperature by two degrees every two hours until it reaches 80 °F (27 °C).
Add 2.5 tsp (14.2 g) epsom salt per 10 gallons (38 L) of water. Refresh water every 3 days.
Add 36 mg Kanaplex per 1 gallon (3.8L) of water to the tank. Wait 7 days.
If no improvement, add 200 mg Kanamycin per 1 gallon (3.8L) of water. Wait 7 days.
Add 200 mg liquid praziquantel per 1 gallon (3.8L) of water. Wait 7 days.

Part 1

Part 1 of 4:

Diagnosing the Ailment

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1
Watch for bloat. Dropsy is a build-up of fluids inside the goldfish. Thus, the first signs of dropsy will be general bloating.^{[1]
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- Look for any unusual increase in size of the goldfish.
- Treating the goldfish at this early stage presents the best chance of saving the goldfish.
Beyond the initial bloating, fluid build-up begins at the goldfish’s head. As fluid builds up under the goldfish’s eyes, they will start to bulge out.^{[2]
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Notice distended scales. This is the classic symptom of dropsy. As fluid build up moves down the goldfish’s body, its scales will start to rise up from its body. When the fluid build-up has progressed through the goldfish’s whole body, it will look like an opened pinecone.^{[3]
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- Pearlscale goldfish are sometimes mistakenly diagnosed with dropsy because their scales naturally have a raised bump in the middle. A Pearlscale goldfish likely only has dropsy if its scales are far more raised than usual.
- Once a goldfish has reached this change it is usually not savable. However, it doesn’t hurt to treat the symptoms and try to cure the underlying disease.

Part 2

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Treating the Symptoms

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1
Isolate the sick goldfish. Dropsy—and its underlying causes—are not contagious. However, the conditions a goldfish needs to recover from dropsy are different than the normal ideal conditions of an aquarium. A second tank of similar size can serve as the goldfish’s sickbay.
- Perfect conditions must be maintained for the goldfish’s immune system to have the best chance to recover.
The water should start out at the same temperature as the water in the goldfish’s original tank. This will prevent the goldfish from going into shock in its new environment.
3
Slowly raise the water temperature. The ideal water temperature for a goldfish with dropsy is 80 degrees Fahrenheit. A relatively high water temperature will prevent bacteria from multiplying.
- Raise the temperature in the tank by a two degrees every hour until it reaches 80 degrees Fahrenheit.
- Use an adjustable aquarium heater so you control the rate of temperature increase.^{[4]
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Add Epsom salt.^{[5]
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Expert Source

Craig Morton
Aquarium Specialist, Aquarium Doctor Inc.

Expert Interview. 21 July 2020.} The kidney’s function is to keep the fish’s internal salt levels balanced with the salt levels in the water. When the kidneys shut down, salt builds up in the goldfish. Increasing the salinity of the tank helps the goldfish to stay in equilibrium with its environment—which will boost the goldfish’s immune system.
- Add 2.5 teaspoons of Epsom salt per 10 gallons of water.^{[6]
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  Expert Source
  
  Craig Morton
  Aquarium Specialist, Aquarium Doctor Inc.
  
  Expert Interview. 21 July 2020.}
- Don’t add too much salt. A high level of salinity will put even more stress on the goldfish’s kidneys.
5
Change the water frequently. The goal is to keep the goldfish in perfect, clean conditions while it recovers from dropsy. Changing the water on a regular basis will help achieve this goal.
- Aim to change the water once every three days.
- Remember to slowly increase the temperature and add salt to the new water.

Part 3

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Curing the Disease

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Realize dropsy has many causes. Dropsy is a symptom of many goldfish diseases. It can be caused by bacterial infections, parasitical infections, toxins, and kidney cysts. There is no way to know the cause of a particular goldfish’s dropsy. Only the first two causes—bacterial infections and parasitical infections—can be treated.^{[7]
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- Since there’s no way to know the cause of dropsy, it makes sense to provide all available treatments.
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Treat any bacterial infection. There are two antibiotic treatments available for treating bacterial infections in goldfish—Kanaplex and Kanamycin. They each target different bacteria, so its important to start with one, check for improvement, and move onto the other.^{[8]
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- Add thirty-six milligrams of Kanaplex per gallon of water to the tank. Continue the treatment for seven days. Watch the goldfish for signs of improvement such as decreased bloating, more active swimming, and increase eating. If you don’t notice any improvement, move on to Kanamycin.^{[9]
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- Add two-hundred milligrams of Kanamycin per gallon of water to the tank. Continue the treatment for seven days and watch for improvement.
- You can purchase Kanaplex and Kanamycin at any pet store that sells fish. If you don’t have a pet store nearby, both antibiotics are available online.
- There are also antibacterial fish foods you can feed to your goldfish to help it get better.^{[10]
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  Expert Source
  
  Craig Morton
  Aquarium Specialist, Aquarium Doctor Inc.
  
  Expert Interview. 21 July 2020.}
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Treat any parasitical infection. There is no well-established treatment for parasitical infections. However, liquid praziquantel has shown some promise. In any case, it won’t hurt to try.^{[11]
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- Shake the bottle of liquid praziquantel vigorously. Add two-hundred milligrams of praziquantel per gallon to the tank. Continue the treatment for seven days and watch for improvement.^{[12]
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- Praziquantel is available at most pet stores that sell fish. It’s also available at online retailers.

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Returning the Goldfish to its Aquarium

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If the goldfish has become more active and less bloated, wait three weeks to ensure the change represents real recovery from dropsy. If the positive change continues, it’s time to return the goldfish to its home tank.
Over the course of three water changes—approximately nine days—reduce the water salinity by 1/3 of a teaspoon. At the third water change, do not add any salt.
Over a period of hours, reduce the water in the isolation tank to the temperature in the tank where the goldfish will be returned. This will acclimate the goldfish to the new temperature so it doesn’t go into shock.
To help prevent future outbreaks of dropsy, perform regular water changes and ensure that the water temperature does not fluctuate more than a few degrees during the day.

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Can dropsy be cured?

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This answer was written by one of our trained team of researchers who validated it for accuracy and comprehensiveness.

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It may be possible to cure a fish in the early stage of being infected by dropsy (bloat, evidenced by such symptoms as a huge, swollen belly and skin lesions on the fish) but the hard truth is that it is difficult to cure. The difficulty is that by the time the fish shows signs of dropsy, its immune system has already been compromised and it is not a healthy fish (healthy fish don’t get dropsy). If the dropsy is diagnosed very early in the infection and prompt treatment is given, it may be possible to cure it through isolation from healthy fish, using appropriate antibiotics, a healthy diet and low stress; follow the instructions above if you’re trying to cure your fish of dropsy.

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Is goldfish dropsy contagious?

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Dropsy itself is not infectious. However, the environmental factors that may have contributed to it could cause other fish to become infected if not addressed (such as spikes in ammonia or nitrite, poor water quality, improper water temperature, stressors such as putting wrong fish together, inadequate nutrition, etc.). The reason a dropsy-infected goldfish should be separated during recovery is to ensure that it isn’t stressed by other fish and you can tweak its environmental needs to aid healing; also, some of the treatment conditions needed for the fish with dropsy are not good for the healthy fish to be subjected to.

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How do you treat goldfish?

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It is unclear what problem you want to “treat,” but here are some suggestions that might answer your concern. First, if you’re dealing with your goldfish dying, read How to Save a Dying Goldfish. If you want to know how to to cure goldfish ich, see How to Cure Goldfish Ich. If you’re concerned about goldfish dropsy, read through the article above. Finally, if you need to know how to handle a goldfish, check out How to Handle a Fish with Care.

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Warnings

When adding Epsom salt, make sure you add only pure Epsom salt. Fragrances or other additives, even some essential oils, can kill your fish.

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