Guppy Dropsy: Early Detection And Fast Fix For Your Pet Fish

Guppy Dropsy
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Last Updated: March 22, 2023 by Flora Gibbins

Fish keepers love guppy fish for their peaceful temperament, vibrant colors, and playful nature. These tropical fish rarely fall sick making them perfect for beginners and hobbyists. 

But then…

Even though guppy fish are hardy, they suffer a few diseases. One such disease is guppy dropsy. 

Dropsy is a condition that affects guppies and other fish. But what exactly is dropsy? What are the symptoms to look for? Is dropsy treatable? If not, how can you prevent it?

This article provides answers to these questions and more.

What Is Dropsy? 

Dropsy refers to a rare medical condition where guppy bodies appear swollen due to excess water or fluids in the body cavity and tissues. The fish have bloated stomachs that give them an oval-shaped belly. Dropsy is also known as swollen belly disease or bloated disease. 

The disease also causes the scales to protrude, which gives your fish a pine-cone look. 

What Causes Dropsy In Guppies? 

The leading cause of guppy dropsy is a compromised immune system. A fish with low immunity is more vulnerable to Aeromonas, a bacterium that causes dropsy. 

Surprisingly, this bacterium inhabits many aquariums with poor water quality. However, it is only harmful to fish with compromised immune systems. But what weakens a fish’s immunity to make them prone to dropsy?

We list the most common causes of guppy dropsy below:

Poor Water Quality

Poor Water Quality

Poor water quality conditions harbor and promote harmful bacteria that weaken the guppies’ immune system. The aquarium water becomes unhealthy if you do not filter the tank, remove fish waste, decaying plant matter, and old foods, perform partial water changes, or vacuum the substrate. 

What’s more, ammonia levels spike into toxic levels in an unmaintained tank. This will stress your guppies, thereby compromising their immune system. 



Stress is an invisible fish killer. Your guppies can get stressed from living in overcrowded tanks, sharing space with aggressive fish, poor diet, internal parasites, sudden water changes, high ammonia and nitrite levels, or other illnesses. 

If a guppy is stressed for long, its immunity will weaken, opening doors for infections and illnesses. 

Poor Nutrition

Poor Nutrition

Guppies are required to feed a healthy and balanced diet. Failure to do so will lead to deteriorating health. Providing poor nutrition will make your guppies prone to infections, including dropsy. 



Your guppies may sustain injuries from living with aggressive tank mates. Besides, your trip home from the pet store or sharp-edged tank decorations can inflict injuries. Regardless of how the injuries came to be, they too can cause dropsy. 

Sudden Water Changes

Dead Fish

In addition, fluctuating water temperatures can stress a guppy. For instance, guppies can survive in temperatures below 70 degrees F for a day or two. However, if they are kept in temperatures below 60 degrees, they can go into temperature shock. This can severely impact their internal organs and weaken the guppies’ immune system. 

Other Diseases

Other diseases

If your guppy is sick, their immune system is already weak. This makes them more vulnerable to developing dropsy since their immunity is low. 

What Are Dropsy Symptoms In Guppies? 

Dropsy can be misidentified as swim bladder disease or bloat. This is why you should learn the symptoms of dropsy:

A Swollen Belly


Guppies, especially female guppies, have a swollen belly when pregnant. The belly retracts to normal size as soon as they release the live fry. However, if your female guppies have bloated bellies after birth, they could be suffering from dropsy.

A swollen stomach is not part of a male guppy’s appearance. So if a male guppy is constantly bloated, it could be a sign of dropsy.

The swollen belly is due to the accumulation of water or other fluids in the tissues and body cavity. The kidneys and spleen are failing at this point, and they cannot clear the water build-up. However, remember that a swollen stomach can also be a symptom of constipation or swim bladder disease. 

Pinecone Scales

Pinecone Scales

Guppies should not look like a pinecone, making this a distinctive dropsy symptom. The affected fish have pinecone scales due to the intense swelling and excess water buildup. At this stage, the scales protrude instead of flushing on the body. 

Curved Spine

Curved Spine

Guppies with dropsy can also have a bent spine. The fluid buildup can generate pressure forcing the spine to bend. A vertical curved spine is a sign of guppy dropsy, while a horizontal bent spine may signify fish tuberculosis

Bulging Eyes

Bulging Eyes

Guppies suffering from dropsy can also suffer from bulging eyes. The excess fluid causes organ failure, causing the leaking tissues to apply pressure on the eyeballs. Guppies may develop pop-eye disease, which may lead to deformation. 

Clamped Fins

Clamped Fins

The affected fish have difficulty swimming around when their belly is swollen and distended. This is why their fins may become clamped to the body.



Dropsy causes your fish’s internal organs to shut down. It makes sense why your fish will become lethargic. 

No Eating

No Eating

Feeding becomes a chore for these sick guppies. They stop eating because they are uncomfortable and in pain. Moreover, not all their organs are functioning. You may notice that the affected guppies will prefer to hide. 

Other symptoms of dropsy are:

  • Stringy feces
  • Bulging anus from fluid retention
  • Discolored gills

Factoid: There are several guppy diseases you need to know and identify before they harm your aqua buddy! Read our article on Guppy Diseases: 16 Life-Threatening Illnesses & Their Cures to help you in saving your per fish.

Can You Treat Dropsy In Guppies?

Yes. Fish dropsy is treatable if it is caused by stress, water pollution, and improper feeding. Even then, treating dropsy is a challenge. Remember that you cannot cure dropsy if your guppies develop it from bacterial infection. 

If you are looking to treat dropsy, try the following: 

Quarantine The Sick Guppy

Quarantine The Sick Guppy

First, you must move the infected fish to a hospital tank to prevent new infections in the remaining healthy fish. Besides, housing the sick fish in a separate tank will reduce their stress.

The quarantine tank should be at least a 5-gallon minimum tank suitable for guppies. Add some water from the original tank to the hospital tank. Doing so will transfer good bacteria to the new setup, and you will not have to acclimate your guppies.  

Use Aquarium Salt Treatment

Next, try aquarium salt treatment. We recommend one teaspoonful for one gallon of water. However, do not directly pour the salt into the quarantine tank. Instead, dissolve the salt into some tank water and add the solution to the quarantine tank. 

The aquarium salt will draw out the excess water from the guppy’s body to reduce swelling. 

Do not dose the tank water twice as this can make the water too salty and hurt your fish more. If you want to dose the tank again with aquarium salts, perform a 100% water change. 

Try Salt Bath

Alternatively, you can use Epsom salt to treat dropsy. Dissolve two tablespoons of Epsom salt with one gallon of water and let your fish enjoy short, daily baths for 30 to 45 minutes. 

Watch this YouTube video about using salt in fish tanks:

Avoid Old Fish Food

Since your infected fish have a weak immune system, switch to high-quality food to make them healthy. You can buy high-quality flake food from the pet store, live food, or prepare blanched vegetables. Offer a varied diet to balance their nutrition. However, this will only prove effective if your fish are eating. 

Use Antibiotics


Antibiotics can also help clear the infection. Consult your vet about proper treatment and directions for use.  

How Can You Prevent Dropsy In Guppy Fish?

It’s easier to avoid dropsy than to cure it. Taking good care of your guppy and observing the following measures will prevent them from suffering from this painful disease:

Perform Regular Water Changes

Perform Regular Water Changes

Polluted water is a major cause of guppy dropsy. So, if you change the water regularly, you can prevent the likelihood of dropsy. Instead of relying on your filter to clean the water, perform weekly water changes. 

The percentage of weekly water change will depend on the number of fish in the community tank and its overall size. Small and heavily populated tanks need more water changes than bigger, less stocked ones. 

Clean The Tank Regularly

Clean The Tank Regularly

You should also maintain a clean tank to prevent ammonia spikes and harmful bacteria. This is achievable by cleaning the filters, vacuuming the substrate, and cleaning the walls.

Water quality in a clean tank is free of bacteria, fungus, and parasites that can make your tropical fish susceptible to dropsy. 

Install A Heater And Filter

Install A Heater And Filter

This aquarium equipment will help you maintain the correct water parameters for guppies. A heater will stabilize the water temperature, so it does not fall below the required range. On the other hand, a filter will clean out the waste to prevent bacteria overgrowth and an ammonia spike.

Avoid Overcrowding

Avoid Overcrowding

Did you know an overcrowded tank is a fast recipe for toxic ammonia buildup? Well, the more fish in the aquarium, the higher their bioload. 

You may argue that you have installed a high-quality filter, but it may not be enough to filter the increased bioload. Moreover, an overcrowded tank often leads to aggression among these peaceful fish. 

Ammonia buildup and aggression can lead to dropsy. But you can prevent dropsy by keeping the correct number of guppies. 

Provide High-Quality Diet

Provide High-Quality Diet

Dropsy in guppies can be a result of poor feeding. But you can avert this by feeding your guppies high-quality foods. Also, avoid foods with more fillers, minimal nutrition, and old. 

Avoid Overfeeding

Avoid Overfeeding

When guppies overfeed, they are prone to constipation or swim bladder disease. When guppy fish suffer from these diseases, their immune system is weakened. As previously stated, dropsy affects fish with weak immunity. But, you can prevent dropsy by feeding your guppies small amounts of food per day. 

Add Compatible Tank Mates

Add Compatible Tank Mates

If you keep your guppies with aggressive aquarium fish, they will get stressed and become ill. This is why you should research the compatible tank mates for your fish before introducing them into the community tank. 

Frequently Asked Questions

Is Guppy Dropsy Painful?

There is no definite answer to this question. However, experts argue that dropsy in guppies is painful since fish can perceive pain. They explain that dropsy is edema in humans, a condition characterized by severe pain, which means that fish also experience pain. 

Is Guppy Pregnant Or Suffering From Dropsy?

A female guppy’s body is rounded, especially when pregnant. This body shape can confuse you into wondering whether the guppy fish is pregnant or sick. Fortunately, you can tell the difference after the female gives birth since the belly will shrink in size. 

If your guppies appear bloated after pregnancy, have a bent spine, and elevated scales, start treating dropsy immediately. 

Is Dropsy Contagious To Other Fish?

Yes. Dropsy disease is highly contagious to other fish in the aquarium, especially if it is caused by bacteria. If your guppy fish have a compromised immune system, they risk catching the infection. However, if they are healthy, the risk is minimal.  

Is Dropsy Infectious To Humans?

No. Humans have a dropsy version of the disease known as edema. Excess water builds up under the skin and can be painful. Fortunately, dropsy is not contagious to humans. Nevertheless, use gloves when handling your sick guppies. 

Can Guppy Fish Recover From Dropsy? 

It depends on the stage of dropsy. You cannot cure dropsy in guppies if the swelling and fluid build-up has caused organ failure. Moreover, the disease is fatal if it is caused by bacteria. 

When Should You Euthanize Guppies With Dropsy? 

If your guppies have a bent spine and pine-cone scales, there is not much you can do to ease their pain and suffering except euthanize them. You can euthanize your pet by administering an anesthetic overdose or mixing their water with clove oil. 


Guppy dropsy is fatal to guppies since it causes organ failure. But, it is preventable if you maintain a clean tank with optimal water parameters. Also, feed your guppy fish high-quality foods and reduce stress. 

If you observe that you have infected guppies in your tank, move them to a separate tank for close monitoring and prevent infecting more fish.

We hope the above treatment options will help you save your sick fish. However, if there is no improvement in the fish’s body, consider euthanizing the infected guppies. 

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