Dropsy Fish Disease—How To Treat Your Fish for Dropsy

By Eddie Waithaka @aquariawise

Dropsy Fish Disease—How To Treat Your Fish for Dropsy

Dropsy is a condition that occurs in fish mostly characterized by the build-up of fluid inside the fish’s body cavity or tissues. Think of the term as an old medical reference for a condition that today would be most likely called edema.

In fish, the soft swelling tissues occur in cavities such as the abdomen, mostly due to the accumulation of water and other fluids.

Even so, as a symptom rather than a disease, dropsy indicates different underlying issues that including bacterial and parasitic infections or organ dysfunction (Kidney and liver).

To treat fish for dropsy, medicines are readily available in pet stores, though the effectiveness of different products varies. Moreover, medications such as antibiotics, antivirals, and treatment for parasites are useful only to the extent you know the direct cause of the condition your fish is in.

That said, it’s imperative to note that treating dropsy is not easy, but if the infection is detected early, you may have a better chance of saving your fish.

Also make sure that the treatment is geared towards correcting the underlying problem and providing supportive care to the fish.

Please note I’m not a veterinarian, and I’m just passing on my experience and things I’ve learned over time, mostly from the internet and keeping fish.

Dropsy in Betta Fish

Dropsy in betta fish is usually not a disease itself, but rather secondary symptoms of other underlying problems inside the fish’s body.

Most times, it is caused by a bacterial, viral or parasite infection that builds up in the betta. Which is a common occurrence, and also pretty easy to spot when you learn the signs and properly observe your fish.

The condition is, however, also linked to other causes in betta fish which include kidney failure, poor diet, and bad osmoregulation.

Generally, the infection first makes its way into a betta fish scales and slowly affects the kidney and liver which makes the fish start retaining unnatural amounts of fluids, and eventually result to the pine-cone appearance or swelling.

If not quickly treated (like in all other aquarium fish), dropsy is fatal and can quickly diminish the life of your betta.

That said, chances of survival are more common with less severe internal infections and immediate treatment.

Common treatments include antibiotics like Kanamycin Sulfate or Maracyn II, though you will need to put the fish in a hospital tank with clean water. And it’s also recommended you add one tablespoon of aquarium salt per gallon to help sanitize the water.

Goldfish Dropsy

Goldfish coming down with dropsy will typically start off with increased body swelling, particularly visible behind the head until eventually, the whole fish becomes bloated.

The the characteristic pine-cone scale appearance.

In advanced stages, the eyes may bulge out due to a large amount of fluid pushing behind them.

Dropsy in goldfish (like any other aquarium fish) is caused by bad osmoregulation which is the inability of fish to rid excess fluid.

Same as betta fish, dropsy in goldfish can be caused by a bacterial infection that may result from varying reasons. The bacteria usually invade the fish’s body while it is weakened and destroy internal organs such as the kidneys which regulate fluid balance.

That said, it is hard to detect dropsy in goldfish with an untrained eye from the side especially on rounded body breeds, but the swelling is quite apparent from above.

However, by the time pine-coning is discovered, most times the damage has usually been done, and the kidneys are shot.

Hence, difficulty in detecting the condition is what makes it so deadly.

For this reason, it is common for fish keepers to euthanize infected goldfish once they are past the pine-cone stage.

Nonetheless, if you catch the ailment early enough, a combination of Kanaplex and Furan 2 can be able to reverse dropsy in goldfish. These should be added to the water together.

Moreover, add Epsom salt to the water as well as this can help draw the fluid out of the bloated fish and establish an equilibrium between the fish body and your aquarium water.

Lastly, don’t stress your goldfish, keep the lights low and ensure the water temperature stays stable when doing water changes.

Also, remember fancy goldfish are less tolerant of cold water, besides, the ideal water temperature for a goldfish with dropsy is 80°F.

What Causes Dropsy Fish?

As I have mentioned a couple of time before, dropsy is mostly a symptom of an underlying illness in fish, meaning it can be caused by varying reasons.

Mostly, the condition occurs when a fish is battling an infection (usually bacterial) which affects the fish’s kidney and make it inadequate at regulating body fluid.

The body fluid hence accumulate in the fish’s body cavities and result in the body swelling referred to as dropsy.

The infection generally affects fish with a weakened immune system occasioned by a poor environment inside a fish tank. Some of the aquarium settings that help bacteria thrive include:

#1— Temperature

Depending on the fish you are keeping, your fish tank should be kept either at tropical conditions or cold water settings when you have fish that prefer cooler tanks like goldfish.

So, make sure you maintain the temperature of a tropical aquarium anywhere from 75°F to 84°F and keep your cold fish tank above 65°F. Although a temperature setting that is at the least 60°F is Ok for the hardiest cold water fish during the cold season.

That being said, it is important to research the exact temperature for your fish and match your aquarium environment to that setting.

This is especially crucial when keeping goldies and bettas because these breeds are often more susceptible to dropsy.

Plus take caution with fancy goldfish as they are less tolerant to cold water than their narrowbody cousins. Keep them in a fish tank with a temperature range between 70°F and 75°F.

#2— Bad Water Quality

Bad water quality in aquariums means having bacteria and chemicals floating in the water that gradually affect your fish and eventually compromise their immune system hence set the stage for infections.

Fortunately, dirt sources in a fish tank are pretty easy to identify and resolve.

First, regular water changes are necessary, at least once a week especially when you have a new fish tank, but you can also do 25 percent water changes in established aquariums with hardy fish.

Moreover, clean your tank and vacuum your substrate to remove any leftover food, fish waste, and plant debris. Also, make sure you clean your plants, decorations and aquarium glass surfaces.

If you suspect there are infectious pathogens in your aquarium, you may want to move the fish to another tank and do a complete cleanup and water change.

However, should you decide to do this, ensure you leave a portion of the gravel unwashed to maintain enough useful bacteria that will recolonize the fish tank once you set it back up.

#3 — Diet and Nutrition

The other common dropsy catalyst resulting is feeding your fish either with the wrong diet or low-quality food which in turn compromises your fish’s immunity.

Therefore, it is important to research your fish preferred diet and assess the quality of food you are feeding them.

Even so, some foods like flake feed also known to cause constipation in aquarium fish, whereas overfeeding results in both constipation and bad water quality.

On the other hand, live foods are infamous for carrying bacteria and parasites hence put your fish at risk.

Nonetheless, depending on the fish you have in your tank, a good tropical flake food should be a staple of their diet, coupled with an occasional serving of live food for omnivorous and carnivorous fish and vegetables for both herbivores and omnivores.

If any of your fish is constipated, consider feeding it peas.

One last thing, always feed your fish with little chunks of food that will fit in their tiny mouths. Plus use floating food when you have top and upper-mid tank dwelling fish and sinking pellets for bottom and lower-mid level dwellers.

What is The Cure for Dropsy?

Dropsy in fish is a deadly condition and is quite hard to treat, for this reason, some hobbyists prefer to euthanize their fish.

However, there is a chance that a fish can be treated and cured of dropsy, but its mostly dependant on early detection and finding a solution to the root cause.

The most common and somewhat effective solution is using antibiotics to treat the bacterial infections responsible for the swelling.

Antibiotics for treating bacterial infections in goldfish and betta fish are available in pet stores. They include Kanaplex and Kamanyan for goldies and kanamycin sulfate and Maracyn II for bettas.

Feeding goldfish with metroplex in food by mixing it with focus is also advisable to combat internal infections.

Even so, there are a couple other crucial remedies you’ll need to use or implement when treating a fish with dropsy.


  1. Treating any parasitical infections with well-established treatments. For instance, liquid praziquantel has shown promise a couple of time in my tank.

  2. Add Epsom salt to keep the fish’s internal salt levels balanced with the salt in water. This is important because when the kidneys shut down, salt builds up on the fish, so increasing salinity in the tank helps the fish stay in equilibrium.

  3. Slowly raise the water temperature in your fish tank to keep the bacteria in the tank from multiplying without shocking your fish. However, you will have to lower the temperature once the fish starts exhibiting signs of recovery.

  4. Since dropsy is caused by a variety of infections, you will want to move the infected fish into a treatment tank to ensure other fish do not get infected in case the condition is contagious.

    That’s all for this post.

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