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Dropsy in Betta Fish: Vet-Approved Causes, Signs, & Treatments

Brooke Billingsley

By Brooke Billingsley

Dropsy is a dreaded word in the fish-keeping community. This condition has a high mortality rate, and many people don’t understand why. This is because many people don’t fully understand what exactly Dropsy is. It’s important to understand the underlying pathology of Dropsy to understand what causes it and how you can give your Betta fish the best chance at surviving Dropsy.

What is Dropsy?

The first thing you need to know about Dropsy is that it isn’t a disease at all. Dropsy is a sign of an internal problem. It indicates that there is some type of systemic infection your fish is attempting to fight. It is usually caused by bacterial infections, but Dropsy can be caused by other problems, like parasites and tumors. The reason that Dropsy is so deadly is that it is a late-presenting sign of a problem, so by the time Dropsy sets in, your fish is already gravely ill.

Dropsy is a build-up of fluid, mainly within the abdominal cavity of the fish. What happens with severe infections is that they eventually lead to organ failure. As organs begin to fail, the body stops functioning properly, which can lead to fluid leaving where it should be, like the blood vessels, and escaping into the body cavity itself. Free-floating fluid in the abdomen is the main identifying symptom of Dropsy.

What Causes Dropsy?

Dropsy is almost always caused by problems related to water quality. Poor water quality depresses your Betta fish’s immune system, leading to your fish more easily picking up infections. Under normal circumstances, your Betta’s immune system would be able to combat infections, but when the immune system is depressed, even simple bacteria and fungi can become deadly.

Poor water quality is usually related to waste build-up in the tank due to poor filtration or aeration. In Betta fish, they can become extremely stressed and get sick easily if their tank is kept too cool. They are tropical fish that require warm water temperatures, and room temperature water is almost always too cool for their needs. Water outside their preferred temperature range can lead to immune system depression, stress, and illness. You may also see immune system depression with travel, bullying and fin nipping, and an overall stressful environment.

Signs of Dropsy

The main sign of Dropsy is “pineconing”. What this means is that your fish takes on an appearance like that of a pinecone. As the abdomen swells with fluid, the scales begin to push outward, creating the pinecone look. This is simply due to the scales being pushed out from the body due to excessive swelling.

Other signs of Dropsy can include the following
  • Swelling of the abdomen
  • Eyes that are beginning to swell and bulge
  • A loss of color in their gills
  • Clamping of the fins
  • A curve developing in their spine
  • Pale feces
  • Swelling near their anus
  • A loss of appetite
  • A lack of energy and movement

How Can I Treat Dropsy?

Please Note

Because dropsy is a sign of an underlying issue, its underlying cause may or may not be contagious. Prevailing standard practice is to quarantine sick fish that show signs of dropsy, to prevent its spread to other fish in the community (in case the cause is contagious and if your betta is in a community setup). However, quarantine is only effective if the disease is caught early on. In advanced stages, the entire tank should be treated.

Ideally, you should move your Betta to a hospital or quarantine tank that has pristine water. Sometimes, this isn’t possible for everyone, which is fine. Just make sure you create a pristine water environment in your Betta’s tank if you can’t move them.

For Bettas, your water parameters (of most importance) should be as follows:

  • Ammonia: 0 parts-per-million (ppm)
  • Nitrite: 0 ppm
  • Nitrates: under 20-15 ppm, ideally under 10 ppm.
  • Temperature: 28°C (or 82.4 °F)

If your water quality is suboptimal, the odds of any treatment working are very minimal to none. It’s also unethical to keep fish in a less-than-ideal environment. If your water parameters are suboptimal, you should do large water changes (35-50%) every other day until you can consistently see acceptable levels of ammonia, nitrite, and nitrates in the aquarium.

Your Betta should be treated with aquarium salt in the tank. Keep in mind, especially if you are adding this to your primary tank, that aquarium salt will not evaporate with water and can only be removed with water changes. If you keep adding aquarium salt without performing water changes, you are slowly increasing the salinity of the tank. You should also feed a high quality, high protein diet during this time.

It is very important to note that the prognosis for most fish with dropsy is very poor, because the sign is often associated with very prolonged illness. Many fish do not handle medication well at this point, due to the failure of multiple organ systems inside their body. However, you can reach out to your aquatic veterinarian for advice on the use of other concurrent medication alongside the salt treatments (these treatments vary depending on the likely cause of dropsy in your betta’s case). It is also advisable to consider humane euthanasia for your fish if your veterinarian deems that the disease has progressed too far to warrant treatment.

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In Conclusion

If your Betta fish develops Dropsy, it can be extremely distressing to you and them. Dropsy is indicative of a profoundly serious problem and is likely to result in the death of your fish. You can absolutely attempt to treat Dropsy, though.

Remember that a fish that is already weakened by illness may not survive the stress of medical treatment. Follow all instructions on any products you choose to use to attempt to treat Dropsy. Don’t double dose or overdose medications, and ensure you only use medication other than salts at the advice of your veterinarian. Remember that an antibiotic will not help your fish and will likely make their condition much worse if their disease is not caused by a bacterial agent.


Featured Photo By: Lienda Yunita Apponno, Shutterstock

Brooke Billingsley

Authored by

After nine years as a veterinary assistant, Brooke Billingsley transitioned to a career as a nurse in 2013. She lives in Arkansas with her boyfriend, sharing their home with three dogs, two cats, five fish, and two snails. A dedicated animal lover, Brooke has a special place in her heart for special needs pets, including a three-legged senior dog and a famous cat with acromegaly and cerebellar hypoplasia. is one of her hobbies, and she is constantly improving her knowledge to care for her aquarium pets. Brooke is an active yoga enthusiast, having obtained her 200-hour yoga teacher certification in 2020. She believes in the importance of continuous learning and dedicates time each day to developing new skills and expanding her knowledge....Read more

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