Betta Dropsy

Betta Dropsy: A Deadly Fish Disease

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If you’re new to betta ownership, you’ll want to learn more about the most common health conditions and diseases that could affect your new fish friend.

Preventing disease is always better than the treatment process. Therefore, it’s important to know how to keep your betta healthy in order to ensure the overall quality of your fish’s health.

If you know anything about bettas, you may have heard of a disease called dropsy. This disease commonly affects many species of fish, though bettas can also be highly susceptible.

In this article, we answer all your questions about dropsy, including how you can prevent it and keep your fish safe.

What Is Dropsy?

Dropsy is more correctly known today as oedema or ascites. Oedema causes swelling of the soft tissues in a body cavity, commonly in the abdomen.

As a result, this creates a dangerous and potentially fatal accumulation of fluid and water. It is a common ailment in many tropical fish species.

The word “dropsy” is actually derived from the old English word “dropesie,” from the old French word “hydropose,” and from the Greek for water, “hydropos.”

However, the term dropsy is not generally used to describe similar conditions in humans nowadays, but it is commonly heard when discussing health issues in tropical aquarium fish.

Dropsy is called so because of the physical appearance of the massive swelling of the fish’s belly. The fish’s abdomen will actually “drop” down. Another common name for the condition is “bloat.”

Is Dropsy a Disease?

Dropsy in bettas is not a disease but is actually a group of symptoms often caused by a bacterial infection. This bacteria is often present in all fish tanks, but the already weak or unhealthy fish are more susceptible.

Vulnerable fish fall victim to dropsy when their immune system is compromised, often by stress. If all the residents in the tank community are highly stressed, it’s not uncommon for the entire tank to become infected.

The good news is that since this disease can be prevented from spreading, only one or two fish become sick instead of the entire tank.

However, this can only occur through the owner’s own careful observation and care of the fish, as well as taking quick action to prevent the bacteria from spreading.

Symptoms of Dropsy in Betta Fish

If you are concerned your fish friend might have dropsy, there are multiple symptoms you can search for. In affected fish, skin lesions may appear, and the fish’s belly fills with fluid and swells up.

This causes severe damage to the internal organs. Ultimately, the fish will die, and the mortality rate is pretty high even with the correct treatment.

Early diagnosis and treatment are the only way of giving an infected fish a chance of survival.

One of the problems for fish keepers in diagnosing dropsy is that there are a wide variety of symptoms of the underlying bacterial infection. Some fish show very few symptoms, while others display a swollen abdomen, skin lesions, or both.

However, in most cases, you’ll notice some or all of the following common indicators:

  • A massively swollen abdomen
  • Scales are pushed out by the swelling, causing a pinecone-like appearance
  • Pale gills
  • Bulging eyes
  • Red, swollen anus
  • Pale, stringy faeces
  • Ulceration along the fish’s lateral line
  • The curvature of the fish’s spine
  • Clamped fins
  • Reddening of the fins or skin
  • Lethargy
  • Refusing food
  • Staying close to the surface of the water

The symptoms of dropsy occur progressively as the condition gets worse:

  • The fish’s internal organs are compromised, especially the kidneys and liver.
  • The fish develops anaemia, so the gills lose their healthy red coloration.
  • The abdomen begins to fill with fluid, pushing the internal organs to one side and sometimes causing curvature of the spine.
  • The fish’s scales stick out from the body, making the fish look like a pinecone.

If your betta displays the pinecone appearance, the infection has become severe and may be incurable.

Is Dropsy Painful for Bettas?

Sadly, Yes.

Your Betta fish will be in a lot of pain if suffering from dropsy.

When your Betta suffers from dropsy for an extended period of time, this can lead to organ failure, leading to the death of your beloved pet. This is why it’s so important to catch the early signs of dropsy before it is too late to be treated.

With dropsy, fluid will accumulate inside your fish’s body, cousin swelling, and major discomfort. This can cause difficulty breathing and loss of appetite and prevent them from being able to swim normally due to their swollen abdomen.

Both of which can be extremely uncomfortable and painful for the fish.

Does Your Fish Have Dropsy or Constipation?

Betta fish are commonly affected by constipation, which is often confused with dropsy. This is often because constipated fish also appear to have swollen stomachs, similar to dropsy.

Treating your fish for dropsy when he is, in fact, constipated can severely stress your fish, making his health problems worse instead of better.

Look closely to see if the fish is passing through faeces normally. If he isn’t, the problem is most likely constipation, which is easily treated.

Constipation is caused by dietary problems and often results from overfeeding your betta or feeding him an unsuitable diet.

Always pay close attention to your fish’s diet and feeding regimen to prevent him from becoming constipated.

You can read a detailed guide on how to feed your betta fish at this link.

What Causes Dropsy?

The bacterium that causes dropsy is usually the common Aeromonas bacteria already present in most aquariums.

Aeromonas only causes serious infections in betta fish with a compromised immune system. That can occur, as well as additional stress from a number of environmental factors, including:

Although stress can trigger a bacterial infection, a short-term or single exposure to stress doesn’t usually compromise a fish’s ability to fight off infection.

Generally, the source of stress must be present for a long time, or several stress factors occur quickly for your betta’s immune system to be affected.

Can You Cure Dropsy?

If you identify dropsy early enough, there is a good chance that you can save your fish. However, if the disease is allowed to progress to the point where the fish’s belly becomes swollen and skin lesions appear, it may be too late for your pet.

That’s because, by that point, irreversible damage has been caused to your betta’s internal organs.

Many expert betta keepers recommend that you should humanely euthanize your fish if he develops these severe symptoms of dropsy.

Not only will that relieve your fish of his suffering, but it can also prevent the spread of the condition to your other healthy fish.

How To Treat Dropsy in Betta Fish

Betta Dropsy

The bacterial infection that causes dropsy is not easy to cure, which is why euthanasia is usually recommended. However, if the infection is spotted early enough and the fish is quarantined for treatment, you may be able to save your betta.

Treating dropsy entails correcting the underlying issues and providing your fish with supportive care while he recovers.

Here’s how to treat dropsy:

  • First of all, move the affected fish to a quarantine tank.
  • Next, add one teaspoon salt per gallon of water to the quarantine tank. Low salt levels help keep the water salinity in line with the fish’s blood salinity by helping maintain the fish’s correct osmotic balance. That helps to remove excess water, which may accumulate in the body and cause dropsy. However, be careful not to add too much salt, as that can harm freshwater fish.
  • Feed the fish frozen, high-quality foods. Do not offer live food if you inadvertently introduce more bacteria or parasites into the tank. Provided that the fish is still eating, improving your betta’s diet is often enough to resolve infection in cases of dropsy that have not progressed too far.
  • Be sure to test the tank’s water quality daily to ensure that the parameters are correct for the fish. Keep the tank immaculately clean and perform weekly partial water changes, adding more salt to the fresh water you’re putting into the quarantine tank.
  • You should treat him with antibiotics if the fish does not immediately respond to the aforementioned treatment. You will need to use a broad-spectrum antibiotic formulated for gram-negative bacteria, such as Maracyn-Two, which you can buy online or from your vet. Follow the manufacturer’s directions for dosage and treat the fish for a duration of ten days to be sure that the infection is eradicated.

Throughout his treatment, keep a close eye on the sick fish for a few weeks after his symptoms have disappeared before returning him to the community in the main tank.

While the infected fish is isolated and under treatment in a separate tank, monitor the healthy fish in your display tank for signs of infection.

Carry out regular water changes on your display tank and test the water daily to ensure the conditions are perfect for the fish.

Preventative Measures

As with any disease, it’s much better to prevent the problem from affecting your fish first than to treat the illness once it’s occurred and you have a sick betta on your hands.

Pretty much all the factors that can cause stress for your betta are all it takes to leave the fish vulnerable to an infection that could be prevented.

Water Quality

By far, the most common cause of stress in aquarium fish is poor water quality, so maintaining your tank and keeping it in the best possible condition is vital.

Be sure to carry out daily water tests on the tank, including the levels of ammonia, nitrite, and nitrate in the water and the pH level. If these levels become too high, your betta will get stressed.

You can keep the water clean and fresh by carrying out weekly water changes, removing up to 25% of the water, and replacing it with clean water that’s been treated to remove the chlorine and other harmful chemicals.

When cleaning out your tank, use an aquarium vacuum to get rid of faeces, uneaten food, and plant debris that has fallen into the substrate.

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Also, remove any dead or dying plant matter before it begins to decompose and pollute your tank water.

Wash the filters thoroughly and regularly in tank water to prevent clogging. Make sure to remove the sludge that could prevent the filter from working efficiently.

Bettas are extremely sensitive to water temperature. Ensure that your tank heater is working properly and that the temperature is constant at 780 F throughout the environment.

You can check that the temperature is evenly distributed throughout the tank by placing a thermometer at the opposite end of the tank to the heater.

Also, site the heater next to the filtration system so that the water is heated prior to circulation around the tank.


Although some company of the right kind is good for your betta fish, avoid overcrowding the tank. Too many fish will create a stressful environment and cause diseases to spread more readily.

As a general rule of thumb, you should allow one inch of water for one inch of fish. Of course, you can only have one male betta fish in your display tank.

They’re not called Siamese fighting fish for anything, and two males will fight, often to the death! However, keeping a sorority of female bettas with your male and a few other peaceful tankmates may be possible.

Overfeeding and Diet

Overfeeding can cause stress in betta fish. Bettas are naturally greedy fish and will keep on eating even when they’ve had enough to satisfy their nutritional needs.

A betta fish’s stomach is the same size as its eye, so you can easily see just how little food your fish needs to keep him satisfied.

Be careful not to feed stale food. As a general rule, dried food, such as pellets, flakes, and freeze-dried food, should be used within one month of opening the packet.

Although a betta’s natural food is live insects and insect larvae, you must ensure that your supplier has a good reputation and obtains his live food from a reliable source.

Although you can breed your own live food for your betta, never be tempted to take insects and larvae from the environment. In both cases, it’s too easy to accidentally introduce bacteria and parasites into your aquarium with live food.

Vary your fish’s diet, giving him a mixture of living, frozen, freeze-dried, and pellet food. That helps to provide variety and guards against problems such as constipation.

Feed your fish once or twice daily, offering just enough food, so it’s all gone within a minute or two.

Also, include one day per week when your fish isn’t fed at all. That fasting day will enable the fish to digest any food still in its digestive system, helping to prevent constipation.

How Long Will a Fish Live With Dropsy?

A Betta fish suffering from dropsy can sometimes live for several more months, but in most cases, if your fish has contracted dropsy, this is likely to be a life sentence.

In situations where an internal infection causes dropsy, the bloating may decrease for a short time but is almost guaranteed to come back far more severely.

There are many sources out there that list “cures” for dropsy. However, most of the time, these temporarily regress the disease before it returns to full throttle.

Is Betta Dropsy Contagious?

Generally, Betta fish that contract dropsy suffers from an already weakened immune system. Dropsy is caused by a bacteria named Aeromonas, so unlike a virus, it cannot be spread to your other fish.

It’s normal to be concerned about this illness spreading, especially if the Betta suffering from it is part of a community tank. However, this bacterial infection cannot be spread between fish, so bettas tank mates should all be fine!

That said, you’ll want to separate fish with dropsy from their tank mates in order to treat them for the illness.

Putting your sick fish in quarantine in a separate tank so that your other fish do not ingest the medication is always the safest option when treating any illness.

Final Thoughts

Dropsy is a common disease that’s usually seen in bettas and other species of tropical fish that are kept in an unsuitable, stressful environment.

If your tank is well-maintained, the fish are fed a correct, healthy diet, and stress is kept to a minimum, outbreaks of bacterial infection are unlikely.

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