Dropsy In Goldfish (Causes, Symptoms, Treatment & Prevention)

Do you suspect dropsy in goldfish that are in your tank right now? If you think they have dropsy, pay close attention.  

We will tell you all you need to know about this goldfish affliction. It’s quite common, so don’t fret- we can help get your fish feeling better again.  

What Is Dropsy in Goldfish?  

It is important to note that the term “dropsy” is not a medical one. Vets do not consider the condition to be a disease. Instead, the term dropsy is a reference to the many symptoms a goldfish will display.  

Dropsy results as the product of a bacterial infection of the fish’s kidneys. The kidneys, which are infected, hold water. This retained water leads to swollen kidneys and disrupts homeostasis in the goldfish, specifically osmoregulation. 

Osmoregulation is how a goldfish keeps its internal fluids in balance with external water. Late stages of dropsy will have goldfish with such a swollen belly that the scales may fan outward.  

Goldfish that are severely sick will not eat, look incredibly unhappy, and might even have trouble swimming, although some fish just swim along as though nothing is wrong. 

What Causes Dropsy in Goldfish?  

Dropsy is actually an old medical term no longer used except for when referring to fish. Nowadays, we might call such an affliction ascites or edema. All these terms mean the same thing; it refers to the swelling of soft tissue within a body cavity, such as the abdomen. 

You will notice your goldfish or aquarium fish have dropsy when you look at them and see their bellies are swollen well beyond an average size. The belly seems to drop down, which may be why fish keepers still use the old term to describe how their fish is looking. It may even look like the fish is bloated. 

Disease of Immune-Compromised Fish  

Dropsy in your aquarium or goldfish is actually a reference to a group of symptoms that arise as part of an infection from bacteria that is present in every aquarium. As a result, fish may be exposed to the bacteria that causes dropsy, but healthy fish do not become affected by the disease. Fish are only prone to developing dropsy when their immune system is compromised, thanks to stress. 

The Bacteria That Causes Dropsy 

The bacteria in question is known as the Aeromonas bacteria. It is a gram-negative bacterium that you find in almost all aquariums everywhere.  

These are called gram-negative because, unlike other bacteria, they don’t adapt to a particular stain when tested using the Gram Stain method of IDing species of bacterias. 

Once again, you only need to worry about this if the fish already have poorly functioning immune systems.  

In a nutshell, keep an eye on the following factors: 

  • Spikes in nitrite or ammonia 
  • Water quality 
  • Nutrition 
  • Transporting your fish (this is very stressful for your finned friends, and if you are moving, you must take extra care to keep the fish as comfortable as possible). 
  • Tankmates that aren’t a good fit (We’ve seen some scenarios where peaceful and aggressive fish are mixed, or goldfish are kept in a tropical tank, etc.- tankmates and tank conditions matter). 
  • Other ailments (such as ich, which we talk about below). 

What Are the Symptoms of Dropsy? 

As the dropsy infection gets worse, lesions on the skin may show up, followed by a belly that fills up with fluid and damage to internal organs. The fish will die if not treated.  

It is actually quite likely the fish will pass away even if you act quickly- the mortality rate of this particular disease is high. Still, you should do all you can to save your goldfish.  

If caught early on, you can treat dropsy, and it is more likely the fish will live. However, the symptoms can vary greatly, so you should know all of them as that will make it easier to treat because you can notice it sooner. 

Major Dropsy Symptoms: Outward Symptoms 

  • The belly is swollen to a large size 
  • Eyes are bulging 
  • Gills are pale in color 
  • Fins are clamped to the sides 
  • Spine develops a curve 
  • Anus is swollen and red 
  • Fecal matter is stringy and pale 
  • Fins fan out and fish resembles a pinecone 
  • Fins are red 
  • Fish are lethargic in nature 
  • Fish do not eat 
  • They swim up near the surface 
  • Body develops ulcers especially on the lateral line 

These symptoms do not happen overnight; instead, they develop and progress as the disease gets worse and worse. 

Dropsy in GoldfishInternal Symptoms 

You will not be able to see these symptoms in your goldfish, but this is what happens internally to dropsy affected goldie.  

  • Internal organs such as the liver and kidneys are affected. 
  • Gills lose color because anemia is taking place.
  • Abdomen is filled up with fluid, and organs get pushed from their normal positions which lead to the spine curve. 

Other diseases your goldfish may suffer from include swim bladder disease, fin rot, and constipation.)

How Do You Treat Dropsy In Goldfish?  

The treatment of dropsy is not easy. Some fish gurus recommend that the fish actually be put to sleep as a means of preventing the spread of the disease to other healthy fish within the tank.  

In some cases, Popeye may happen, and if this is the case, things aren’t looking good for the fish tank. 

However, if you are able to detect the disease early on, and the fish are quarantined with an adequate course of treatment, you very well might be able to save your affected fish. 

The idea behind a proper treatment plan is to correct the major underlying issues and provide support for the fish that isn’t feeling well. 

Steps to Treating Dropsy 

The ways to treat dropsy are not always going to work; we want to make that abundantly clear. If the fish has reached the pinecone stage of the disease, chances are it is too late. However, don’t give up and try your best.  

  1. Do you notice the scales sticking out behind the head of the fish? If so, begin treatment right away.  
  2. The quarantine tank should just be like a hospital room for a fish- a plain fish tank with nothing more than filtration, air pump, cover, and water. You should also place the quarantine tank onto a dark surface as the darkness may soothe a fish who is feeling down. A typical quarantine tank is just a small, ten-gallon deal that is suitable for one or two fishes. Make sure water conditions are perfect, so the fish has the greatest chance of recovery. 
  3. Begin by placing your goldfish into a sick or quarantine tank. Do not catch the fish using a net; this could damage him. Use a clean and clear plastic bag to do this. Now add in some non-iodized healing salts. You can use aquarium salt, which is bought at a local fish store, or you can use Epsom salts. Two teaspoons of Epsom salts per gallon is appropriate. 
  4. Feed your goldfish quality foods. Opt for fresh foods if possible; if not, get the highest quality food your local fish shop has around. It will provide the animal with much-needed nutrients.   
  5. Keep a close eye on the quality of the water each day to ensure it is optimal.  
  6. Slowly but surely raise the temperature in the quarantine tank. We know goldfish love temps of 68F to 74F (or 60-70F when referring to shubunkins or comets). Raise the temp up to 80F as this will prevent the bacteria from reproducing. You may also add a bacterial treatment, Kanaplex is a popular one, but any kanamycin medication will do. Be sure you follow dosage instructions to the tee.  
  7. Treat your fish for seven days. If you do not notice an improvement in your fish after three days, try treatment with another medication such as Augmentin.  
  8. If you notice your fish is still eating, continue to feed live foods and medicated foods that help treat dropsy. 
  9. Keep this treatment going until you see an improvement in your fish’s health. Once the swelling has vanished, reduce the amount of salt put into the tank at each water change. After your fish is behaving like himself for a few weeks, you can place him back into the main tank. 
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How Do You Prevent Dropsy?  

Thankfully, preventing dropsy is not so difficult when it comes to fish care. It simply takes some prevention on the part of the owner. Your biggest method of preventing dropsy is going to be reducing the stress your goldfish feel. 

Water Quality Matters 

More often than not, stress comes about as a result of poor water quality. Here’s what you can do to keep water quality in good shape. 

Nitrites, on the other hand, come from fish excrement. If you have live plants, the decaying of the plants can cause this, also. Filters that are dirty may also lead to nitrite spikes.   

There should be NO nitrite at all in your fish tank. Nitrites lead to suffocation, and this is why we see fish at the surface gasping for air. Keep the tank clean with a gravel vacuum and keep algae cleaned up. Perform regular water changes. A nitrite test kit will keep you in the know. 

Other Steps to Follow 

  1. Keep filters nice and clean. We change our filters out every two weeks. Keep them in ample stock, so you don’t get caught without one during a routine cleaning. It helps to buy in bulk. 
  2. Do not overcrowd, or overfeed, your fish. Keep the amount of fish appropriate for the tank size. Feed only what your fish can eat within one minute.  

Check If Your Fish Are Stressed Out 

If all your fish in the tank are feeling stressed out, the whole tank can become infected. Or you might just see a couple of the fish fall ill. It is important to monitor the tank closely every day to keep the fish healthy and catch it fast.  

Now let’s talk about some ways that fish become stressed out.  

  • Look for a fish that has lessened appetite. Similar to humans, extreme stress can cause us to forego eating.  
  • Diseases: Dropsy is one disease, but other diseases like ich can really stress a fish out. If you notice white spots (this is ich) on your fish, talk to a vet or seek help from an over the counter fish medication at your local pet store ASAP.  
  • Surface Gasping: If you see a fish shooting to the surface and sticking his mouth up for oxygen, this is a signal that stress is present in your tank. Poor water conditions that has no oxygen can cause this.  
  • Weird Swimming: You know how your fish swims. Some swim in the middle of the tank; others love the surface, etc. But if you notice your fish swimming in odd ways, crashing into the sides, doesn’t move, or locks his fins to the side, rubs at the gravel or ornaments, the fish is likely under a lot of stress. Make sure to talk to a vet about what to do to get them feeling better. Test the quality of the water. Remove any tank mates who may be stressing out the other fish. 

How Much Stress Can They Handle?  

A short-term stress exposure is NOT going to hurt the fish long term. For example, one stressful scenario is not going to kill a fish. However, if a fish is continuously exposed to stress, the immune system will be negatively impacted. 

It may seem like a complicated task to keep goldfish stress free, but thankfully it is not. Just make sure to do regular water tests. Keep the tank in a quiet place and keep only as many fish as your tank can handle. 

Other Things to Take into Consideration  

  • Tankmate Trouble: You don’t get along with every single person you meet. Fish don’t, either. If a fish is living with too many others or is a peaceful fish living with aggressive fish, this can lead to stress. Make sure your fish are with others like themselves. Also, make sure your fish have plenty of hidey holes to go into in case they need a break. Make sure food is evenly distributed, so everyone has a chance to eat without fighting for food. 
  • Poor Water Conditions: The conditions of the fish water can really have an impact on your finned friends. If the tank is not maintained well, fish aren’t healthy. They may gasp at the surface for air. The water levels may get high in ammonia or nitrate (This can also cause ammonia poisoning). Even those of you with saltwater tanks can notice stress in fish that aren’t kept in properly salted tanks. Whether you’re keeping goldfish, tropical fish, or saltwater fish, you have to keep water conditions at an optimum level. 
  • Miscellaneous: Other stressors can happen to a fish. Keeping the tank in a very noisy area is one way to stress out the fish. Kids may pound on the glass because they don’t know any better. Dogs or cats may paw at the tank. An improper diet can also cause your fish to stress out. Improper chemicals added to the goldfish tank can also lead to stress.  

Is Dropsy Contagious?  

There is some good news- dropsy itself is not contagious. That being said, fish that are affected by the disease should be placed into a quarantine tank. It is just a matter of precaution and also helps you more easily focus your attention on the sick fish.  

Furthermore, a fish that is already compromised won’t have to deal with further tank issues (such as ammonia or nitrite). 

Here are the steps to follow so you can safely isolate the sick fish 

  1. Get the hospital or quarantine tank ready to go. Keep the tank bare bones; it just needs a filter and a heater. Try to keep the quarantine tank the same temp as your original tank. 

2. Now, make a salt bath. Do this by adding just 2.5 teaspoons of Epsom salts per ten gallons of water to the hospital tank. The idea here is that the magnesium sulfate found in the Epsom salts will pull the excess water out of the body of the fish, which could help bring swelling down. 

3. Make sure you have antibacterial fish food available for the goldfish. You can buy this at a local fish store or make up a batch of your own by taking a 1% mixture of fish food plus tetracycline or chloromycetin, both of which are antibiotics. 

4. Keep feeding the fish the antibiotic food and watch their progress for 7 to 10 days. 

After 10 days, if you notice no signs of health-improving or the dropsy gets worse, it is likely that the fish is not affected by a bacterial infection. If your antibiotics do not heal and the salt bath is not effective, there is likely nothing more that can be done. 

Chances are dropsy cannot be cured if all steps are taken and no improvement happens. 

However, you can check with a vet to see if there are other solutions or consult with the employees at a local fish shop. 

Is Dropsy Fatal? 

Yes, the unfortunate truth is that the condition of dropsy in fish is fatal. The mortality rate of dropsy is quite high. 

The best thing for you to do as a fish owner is to prevent dropsy before it begins. The way to do this is by making sure the tank is nice and clean at all times. 

You should arm yourself with an arsenal of cleaning products and fish tank supplies so that you are always prepared to clean at a moment’s notice if you see things get a bit messy. Goldfish are messy fish and need frequent cleanings. You should schedule the cleanings each week to occur at the same time, so you are always consistent, and you make it a habit. 

Some good ways to keep your fish tank clean and neat include using a gravel vacuum, which sucks up the fecal matter, plant bits, and uneaten food, and using algae killer or scraping away the algae in the tank. Buy filters in bulk and make sure to take apart your filter once a month to clean it thoroughly. 

You can also clean off aquarium décor in a safe way by cleaning them one at a time. Clean a different one each week. You can do this using a bleach solution of 4 tsp of bleach to 2 gallons of water.  

Soak the décor in the bleach mix for 2 minutes and then rinse it with water for 5 minutes. Use a bristle brush to get rid of any dirt. Then place the décor in a bucket filled with a dechlorinating mixture and soak for 15 minutes before putting it back into the tank. 


In summary, the good news is that dropsy is not something you have to worry about if you can do one simple thing: maintain optimal water quality. That’s all you have to do! 

And with daily water checks, appropriate feeding, and weekly tank cleanings, the appearance of dropsy will likely never happen to your fishy friends.  

That being said, you should never say never. Make sure to have some medications on hand as well as a quarantine tank available in the event that you have to treat a sick fish.  

Best of luck, and enjoy your fish even more by checking out other helpful articles on our website.