Dropsy In Cardinal Tetra: What It Is And How To Treat?

If you are thinking of keeping Cardinal tetra, there are a few things that you need to know and keep in mind. First, this fish’s disease is a significant problem that arises after keeping the fish in an aquarium. Among the many conditions, dropsy is the most prevalent in Cardinal tetra.

Dropsy in Cardinal tetra is a condition that can occur due to an injury, illness, or infection. It occurs when the body tissues compress, and fluid accumulates in these areas. Dropsy affects all body parts – head, eyes, mouth, etc. It can also indicate other problems such as liver damage or kidney failure.

Dropsy can lead to death if not treated quickly. So every pet owner needs to learn how to diagnose and treat this condition. Thus, this article will be all about dropsy in Cardinal tetra.

Dropsy In Cardinal Tetra

Dropsy is a disease more common in fish than in any other pet. It can occur due to a bacterial infection, parasitic infestation, or even severe kidney failure.

Aquarists refer to the disease as dropsy because of its effect on specific internal organs. It causes them to become swollen with fluid (edema). This swelling becomes visible as tumors in the fish’s body.

As a result of swelling, air bubbles trap under the scales of a tetra and cause imbalance. Besides this, malnutrition, poor water conditions, and viral infection can also cause the fish to drop.

If you spot an afflicted Cardinal tetra, there are some effective treatments that you can apply for this disease, such as a combination treatment involving Kanamycin and Acriflavine-Zinc. This combination usually cures the problem. However, it is crucial to follow the dosage and treatment time correctly.

What Are The Causes Of Dropsy In Cardinal Tetra?

There are various causes for dropsy in cardinal tetra, but the most common infection is Aeromonas or Pseudomonas bacteria. These bacterial infections occur due to poor water quality and low immunity levels in the fish.

Moreover, some of the causes of dropsy in cardinal tetra might be:

Physical Damage

Physical damage can cause Ich to spread through your tank. In addition, physical damage allows the parasite ich to break into the cardinal tetra’s body.

Cuts or wounds can become infected with bacteria, most commonly ich parasites. The cardinal tetra’s immune system will fight off the parasite causing this infection. While at the same time fighting off any other illnesses that may be present in its body after an injury caused by an outside force.

Bacterial Infections

Bacterial infections are common in aquarium fish. There are many ways to contract these infections, such as the water, food, and other fish that may have an illness themselves. Some bacteria may be harmless to the fish. But others may lead to a systemic bacterial infection that can cause cardinal tetra drop. Such as Aeromonas bacteria.


Cardinal Tetras are very susceptible to parasites because of their small size and intimate living environment with fishes. There have been reports of several types of parasite infestations on cardinal tetra. Moreover, the most common parasite in these fish is Ich.

Inadequate Diet

Lack of proper diet encourages the Cardinal tetras to feed on plants and wastes present in the tank. So, there will be a higher probability of them contracting from dropsy.

Unhealthy Water

Tap water is not safe for aquarium fish if you do not treat it before use. Most tap water has chlorine or chloramine, which damages aquatic animals’ gills and makes them sick.

Improper or Wrong Medication

Using inappropriate medication will not only harm the fish but also other inhabitants in your aquarium. So, always check if you are using the right kind of medications(approved by Vet) before applying them to your tank water.

Lack of Good Hygiene Practices

Maintaining good hygiene practices in your aquarium is vital to keep the fish healthy. You should always clean and change the filter regularly. So, perform regular tank cleaning for better water quality, ideal for aquatic life.

It may also be hereditary, where some fishes are born with a weak immune system that can’t fight off the disease.

Improper or No Quarantine Period

Quarantine is the process of keeping sick fish in a separate tank to prevent them from infecting other healthy fish. If you do not quarantine your new or sickly fishes, they will most likely suffer from Ich infection. And this will cause problems for all the other inhabitants in your aquarium.

What Are The Symptoms Of Dropsy In Cardinal Tetra?

Dropsy usually occurs due to swelling in the body of a fish, particularly around the head and abdomen.

Besides this, other symptoms that indicate dropsy in Cardinal tetras are:

  • Loss of appetite.
  • Noticeable swelling in the body, particularly around the head and abdomen
  • There is an abnormal bulging on both sides behind its gills (where the pectoral fins are). Sometimes a more extensive protrusion at the front end of your fish hides them. It is where his belly button should be.
  • When there is a bulging just above the anal fin (on the lower back of your fish), you can usually find a black spot. It helps identify Cardinal tetras from other types of tropical ornamental fish. It’s unique and only seen in this type.
  • The belly area becomes very bloated, looking as if filled with air.
  • Fins are fragile and tinged with red or brownish coloration spreading out from the tips of fins to the body.

How To Treat Dropsy In Cardinal Tetra?

If you notice any of the above symptoms, it’s best to take immediate action.

When it comes down to dropsy, there’s no cure for this illness as time passes by very fast. It can take up days or even months to end the life of your fish. So, treatment is the most for a longer life of your fish.

Here are a few steps to treat dropsy in Cardinal tetra are:

  • First, isolate your fish from the tank, provide them with a hospital tank, and ensure ideal water conditions.
  • Feed your fish only on medication food available in stores near you or online to treat dropsy effectively.
  • Use medicine like Metronidazole (brand name: Flagyl) to treat Cardinal tetra disease effectively.
  • Do frequent water changes to maintain the right amount of nitrates and remove all traces of ammonia from your tank.
  • Include some salt in the aquarium as it reduces stress, also helps with healing. In addition, salt is a crucial element for fish with dropsy symptoms. It makes them feel more comfortable during their illness period.

Keep creating awareness about dropsy to educate everyone around you and prevent this disease in cardinal tetra fish.

How To Prevent Dropsy In Cardinal Tetra?

Dropsy is a disease that can be fatal. So, it would be best if you did what you could to prevent any of your fish from contracting this illness.

To prevent the contraction of Dropsy In Cardinal Tetra, here are a few things for you to keep in mind:

Regularly Change The Water

Keep your aquarium water fresh and clean. The best way to do this is by performing 20-25% weekly water changes. Do not change all of the water at once, as this could also be dangerous for your fish. It’s okay to perform them less than that but don’t skip it entirely.

Use A Filter

Cardinal Tetras are sensitive to water conditions, so the aquarium must have a filter. They will help siphon out harmful toxins from your aquarium while simultaneously oxygenating the water for your fish.

Use Stress Coats

If you ever forget or choose not to use a filter, then at least be sure to give your fish a stress coat. Stress coats help reduce the amount of chlorine in your aquarium water and help to keep them healthy.

Feed Your Cardinal Tetra Properly

The cardinal tetra comes from the bright red spot on the dorsal fin. They are omnivorous and eat live foods like brine shrimp and daphnia, frozen bloodworms, and tubifex worms. However, they also eat flakes, so this is something that you will have to consider as well.

Ensure Proper Water Condition

Finally, make sure that there is a proper amount of oxygen in the water at the correct temperature. If your aquarium does not have an air stone or something similar, you can also use a pump instead. Be sure to keep everything well maintained.


Overall, the fish will not fight against any infections that come their way.

Unfortunately, there is no cure for dropsy in cardinal tetras. However, if you notice the symptoms of dropsy early on, it might be possible to provide medications to slow down or stop the further growth of cysts and tumors. In addition, it can help your fish to live out its life with dignity.

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