Dropsy – Causes, Symptoms, and Treatment

Minnow with Dropsy
Zebra Danio with severe Dropsy

Dropsy is a condition common among aquarium fish and is typically identified as a symptom rather than the actual disease. A fish showing signs of dropsy may be suffering from underlying problems that need to be separately addressed in order to solve the problem. For fish enthusiasts, here’s what you should know about Dropsy.

Signs and Symptoms of Dropsy

The defining symptom of dropsy is bloating. The term itself was originally used to describe swelling caused by an accumulation of fluids, primarily along the tissues and body cavities. Fish DropsyThe swelling is mainly located in the belly but this is not always the case. In some instances, other symptoms become obvious such as a pinecone appearance where the scales stand out, the anus becomes swollen, the eyes bulge out, the gills are pale, and the feces becomes stringy. You’ll also notice some behavioural changes such as lethargy of the fish (hiding or staying at the bottom of the tank most of the time), staying near the surface, and apparent lack of appetite.

Note though that these symptoms are progressive. This means that as the condition advances, you’ll be seeing more and more of the above symptoms, starting with the onset of anemia and the loss of colour of the gills. From there, the abdomen starts to swell up and the digestive tract is affected, preventing the fish from properly digesting or excreting.

Early Warning Signs

Like all health problems, dropsy is best treated before the physical symptoms start to become apparent. During this time, you have no other sign to go on but behavioural changes which can be easily noted if you are observant when it comes to your fish. Typically, a fish suffering from dropsy will stop eating altogether, often hiding in just one part of the aquarium and steering clear of its peers. This lack of appetite usually extends for two to three days before the belly starts to swell. Ideally, treatment should be started on the second day you notice some problems with the eating habits of the fish.

Fish Types Affected

Dropsy is not limited to specific breeds of fish. You’ll find that any type kept in the aquarium can develop this particular infection although goldfish seem to be the ones generally affected by the problem. Note though that fishes with a low immune system are more likely to suffer from this condition. If your pet fish are also constantly stressed out, dropsy may become apparent in more than one of them in the tank. As an owner, it is your duty to observe the inhabitants of the aquarium and make sure that there are no environmental factors that could trigger the problem.

Causes and Prevention of Dropsy

There are several possible causes of dropsy, but the underlying problem stems from negative bacteria which lead to the infection. The infection takes hold of the fish with a weak immune system, the weakened state often caused by the following problems:


The fish tank should be kept at 78 to 80 degrees Fahrenheit – the perfect temperature to promote digestion in fishes. Note though that the number is variable, depending on the kind of breed you have. Ideally, you should research the exact temperature preferences for your fish and set your aquarium to that setting. This way, you’d be 100% sure that the environment is to your pet’s liking.

Bad Water Quality

Bad water quality means bacteria floating in the water, thereby compromising the immune system and increasing the chances of dropsy. Fortunately, you can easily maintain water quality through proper hygiene. This includes cleaning the water filter on a routine basis, using the proper aquarium cleaning agents, and generally making sure that your aquarium maintains a balanced environment for the proper health of the fish.


Of course, don’t forget the possibility of improper nutrition which usually stems from feeding your fish poor quality food. Make sure you’re giving them approved brands with some fresh servings thrown in for better health. A good fresh food feed would be a shelled pea, provided at least twice in the day. A shelled pea is of the right consistency and nutrition to keep your fish healthy, especially when suffering from dropsy. Note that the routine of your feeding also comes into play. Ideally, fish should be sped sparingly and no more than twice a day.

Other contributing factors to dropsy include bullying of other fishes, thereby causing stress, and any physical injury the fish might have. A newly transferred fish might also show symptoms due to the stress of being moved to a different tank.

Possible Treatments

Dropsy is not something you can cure instantly, bearing in mind that there are several possible reasons for it. However, fish enthusiasts can try to address the problem and eventually cure the condition. It is not unheard of for a fish to recover from dropsy, but it does require care and attention on the part of the owner. That being said, following are the steps to care for a dropsy-infected fish.


The first step in treating dropsy is through quarantine. Although the condition is not always contagious, quarantine of the infected fish is an excellent precaution to make sure that none of the others will be infected.

Salt Treatment

Once you’ve isolated the fish, it’s time to add some salt into the aquarium of the infected fish. The rule of thumb is that you have to add 1 teaspoon of salt for every gallon of water. Change the water on a routine basis, still adhering to the 1 teaspoon for every 1 gallon added to the container.

Feed Healthy

Of course, don’t forget to start feeding the fish quality food. Again, shelled peas would be the best option here.


Lastly, drop some antibiotics into the tank. Make sure to ask your vet regarding the amount of antibiotics that should be placed inside. Note that there are medications specifically for aquarium use so if you find those, just follow the instructions provided.

Observe the remaining fish in the original tank. It is recommended that you also perform a clean sweep in the healthy tank to make sure that no other fish will have the problem, especially if no symptoms are showing just yet. Follow the tips given above starting with the salt treatment.