Dealing With Dropsy in Aquarium Fish

Dropsy in Aquarium

Have you heard of a medical condition that causes the swelling of soft body tissue cavities called Dropsy? Dropsy is actually an old term for what is now called edema.

The swelling caused by a Dropsy may appear in places like the abdomen due to an accumulation of other fluids and water.

The English word Dropsy is derived from the old French word hydropse and the Greek work hydrop which means water.

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Symptoms of Dropsy in fish aquariums

Even though the old English word Dropsy if hardly used human medical science in the present day, it is used to describe a certain health issue that affects aquarium fish.

Fishes affected by this condition appear to have swollen abdomen which explain exactly why the term Dropsy which was originally used to refer to a human condition, is now used to describe this fish condition. The belly of a fish affected by Dropsy drops down and it’s sometimes called a bloat.

A disease of immune compromised fish

Dropsy is finned creatures is actually a gathering of cluster of symptoms that is caused by an infection caused by a certain kind of bacteria that is usually present in every fish tank.

Because of the presence of this bacteria is every aquarium, almost any fish can become home to this Dropsy causing organism. However, healthy fish are less likely to fall prey to this sickness.

The only thing that can make a fish susceptible to an infection from this bacteria us when their immune system has been weekend or compromised by some stress factors. If all the fish in your aquarium have been seriously stressed there is a high tendency that the entire tank will become infected.

In fact, it is very common for this to happen though there are cases where only a few of your fishes will suffer from Dropsy when a swift action to restrict the spread of the bacteria is taken.

What are the signs and symptoms of Dropsy?

As the Dropsy infection progresses, you may notice the appearance of skin lesions, the belly of the fish becomes filled with fluid and appears to be swollen, the internal organs of the fish gets gradually damaged and the fish eventually dies.

The intriguing part is that even though swift action is taken to address the problem of this bacteria, the mortality rate remains high. Because of this, a successful treatment has become very unlikely unless your fish is diagnosed at a very early stages of the infection.

The symptoms of this bacterial infection can vary largely. Some of your fish may display skin lesion, some may have the expected swollen belly, while some others may show little or no symptom even though they have been infected and this makes early diagnosis difficult a majority of time.

Symptoms that may be observed includes both behavioural and physical, for example;

  1. Grossly swollen belly
  2. The anus might become red and swollen
  3. Scales that stand out with a pine cone-like appearance
  4. Eyes that bulge
  5. Feces that is pale and stringy
  6. Gills that are pale
  7. A spine that is curved
  8. Ulcer on the body, along the lateral line
  9. Swimming near the surface
  10. Fin clasped together
  11. Refusal to eat
  12. General lethargy

As the disease advances, these symptoms gradually begin to show up.. The fish’s internal organs get affected especially the kidney and the liver. The fish might suffer from anemia and that will cause the gills to lose its healthy red colour.

As the fluid fills the abdomen of the fish, internal organs are pushed aside and the spine of the fish could become curved. Scales will also protrude from the body of the fish and it look like a pine cone. This last symptom is a classic indication of a serious infection.

Causes of Dropsy in aquarium fish

The specific organism that cause aquarium fishes to get a dropsy is the  Aeromonas bacteria which is very common and belongs to the family of a group of bacteria called gram-negative that always makes themselves present in almost every aquarium.

This bacteria is referred to a gram-negative because it reacts to a very common gram-staining identification procedure.

The infection can only cause a serious illness to a fish whose immune system has already been compromised. The weakening of a fish immune system could be as a result of any of the following

1. Ammonia or nitrate spikes
2. Poor water quality
3. Stress from transportation from the pet store
4. A significant drop in fish tank water temperature
5. Aggressive tank mates
6. Improper nutrition
7. Other diseases

Generally speaking, a short term or single exposure to stress such as transportation will not compromise this pets ability to battle infection in any way. Which means that the exposure to stress must be present for a long period of time, or a series of other stress factors  must occur successively in order for the fish immune system to be compromised.


Most of the time we target the root cause of an illness and attempt to eliminate it but I’m the case, the infection that leads to dropsy is not cured easily. Some fish experts will suggest that ask infected fishes in your tank be euthanized to  help prevent the spread of the infection to the healthy fishes.

However if you are able to detect the infection at an early stage you just might be able to save the lives of the affected critters. Treatment in this case is targeted towards correcting the underlying problem (Which is not an easy task)  and providing care to support the sick fish.

You will have to transfer the sick fish to a hospital fish tank, add one teaspoon of salt per gallon of water to the hospital fish tank, treat the sick fish with antibiotics, and finally feed the fish with only high quality food

It is very vital that you separate the infected fish from the healthy ones and change the tank water immediately you quarantine the infected fish. After you change the water in the original tank, pay close attention to the seemingly healthy fishes to easily spot anyone showing signs of an infection.

Preventing dropsy in your aquarium

Prevention has always been better than cure and that holds true in the case of dropsy. Make sure to limit activities that will cause your fish to be stressed and also make sure to feed your fishes with only fresh and good quality food.

Keeping your tank clean is also very vital if your fish must stay healthy so you are required to dedicate some time to cleaning. If you are feeding your fish with flake food, make sure to exhaust a pack within one month of opening so that it doesn’t lose nutrients. Overfeeding your fish can also be dangerous just like underfeeding them.

If you pay attention to the listed preventive measures a dropsy outbreak becomes very unlikely.

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