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Velvet Disease in Betta Fish: Symptoms, Treatment & Prevention

Genevieve Dugal

By Genevieve Dugal

betta fish fading color

Betta fish (Betta splendens) are little fish with strong personalities that many people keep because of their bright and shiny colors. But, on the other hand, they are not easy starter fish, contrary to what some unscrupulous pet sellers may suggest. Indeed, betta fish require special care and cannot be kept in tiny jars that serve as a decoration on the corner of a table.

But if their aquarium is maintained in the best conditions, with clean and warm water, filtration, enrichment like plants and caves to explore, and regular feeding and tank cleaning, bettas can live a long life and be happy. On the contrary, bettas tend to suffer from parasitic, fungal, or bacterial diseases if the conditions of their tank are not suited to a healthy life.

One of those parasitic diseases that can have disastrous consequences for betta fish is velvet disease, which must be treated as soon as the first symptoms appear.

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What is Velvet Disease in Betta Fish?

Don’t be fooled by its fancy name: velvet disease is a condition that can cause serious problems in fish if left untreated. It is caused by a microscopic parasite called Oodinium. Tiny golden-yellow spots develop on the fish that appear to be dusted or scattered over the head, fins, and body. By this time, the infestation is already severe. This disease is also called rust or gold dust disease. It can affect all types of fish living in freshwater, but unfortunately, our dear little betta fish are generally more susceptible to this disease.

Certain factors that cause stress in betta can also put them at a higher risk of developing velvet disease, such as:
  • A dirty tank
  • Poor quality water
  • No water filtration
  • Large fluctuations in water temperature
  • Poor immune system
dirty aquarium tank
Image Credit: Maverick Ace, Shutterstock

What Are the Symptoms of Velvet Disease?

The symptoms of velvet disease vary depending on the severity of the infection. Besides, it is not easy to spot the damage caused by the parasite at the beginning of the infestation, but one can notice that the fish’s body is covered with a thin “golden” or “rust-colored” layer, much like velvet.

The behavior of the contaminated fish will also change: it will appear sluggish, weakened, will swim with contracted fins, and rub its body against the walls of the aquarium in an attempt to dislodge the parasite. You may notice a loss of appetite, and the colors of the fish will appear duller. Your betta will also spend more time on the surface of the water trying to absorb more air; this is a sign of difficulty in breathing due to the destruction of the gill epithelium by the parasite, which reduces the gas exchange surface.

As the disease progresses, small white-yellowish dots appear on the fish, and a kind of mucus may be visible on its body, which is a defense mechanism of the betta’s immune system.

Finally, in the most advanced stages, the betta will exhibit the following symptoms:
  • Ragged skin
  • Opaque eyes
  • Ulcers
  • Clamped fins
  • Bulging or protruding eyeballs (also called exophthalmos, or Popeye disease)
betta fish popeye
Image Credit: BankZa, Shutterstock
  • Note: In any case, as soon as you see the appearance of one or more of these symptoms, seek advice from your veterinarian without delay. Early diagnosis will give you a better chance of saving your sick betta.

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Is Velvet Disease Contagious?

Yes, velvet disease is very contagious. Besides, be aware that infectious diseases in fish are often the most problematic because a single individual can quickly infect all the others. So don’t wait before treating your betta!

How Long Does Velvet Disease Last?

The life cycle of Oodinium lasts between 10 and 14 days. On the other hand, it is difficult to know exactly when the disease will be eradicated, as the betta is usually not affected by only ONE parasite. Thus, depending on the parasite’s life cycle phases, the treatment you choose may last between 14 and 20 days or even longer. Indeed, the treatment must kill the parasites at each stage of their life; otherwise, the infection may reappear.

But the good news is that this pathology can be treated well with commercial antiparasitic products.

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How To Treat Velvet Disease in Betta Fish in 3 Steps

1. Light up your fish with a flashlight

One of the ways to recognize velvet disease is to direct a light source directly at the fish. The light will help you distinguish the golden or rusty sheen that this disease produces on the fish’s scales. As mentioned above, your fish will show other symptoms, such as lethargy and a loss of appetite, or it may frequently rub against walls and objects in the aquarium. It could also have clamped fins.

It is possible to prevent the appearance of this parasite by regularly adding aquarium salt and a cleaning product to the aquarium. You should add one teaspoon of aquarium salt per 2.6 gallons of water.


2. Use commercial treatments

Table or sea salt helps reduce the spread of the parasite, but this treatment is insufficient for completely annihilating the disease.

Other drugs can be added directly to the water to complete the treatment:
  • Copper sulfate
  • Methylene blue
  • Formalin
  • Malachite green
  • Acriflavine

Follow the instructions provided for each treatment and continue to treat the water until your betta fish are no longer showing symptoms.


3. Clean and sanitize the entire aquarium

Since velvet disease is highly contagious, you should always isolate the sick fish first, but you must also treat the entire aquarium. You can put a drop of cleaning product per gallon of water, but it would be better to follow the directions of the product you have purchased.

  • Note: Some enthusiasts and fish keepers recommend increasing the water temperature in the environment of an infected fish to speed up the life cycle (and death) of those parasites; however, this method can put additional stress on your betta. It is, therefore, essential to check with a veterinarian or fish specialist before performing such a shock treatment.

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How To Prevent Velvet Disease in Betta Fish

It is always best to prevent diseases before they appear. Velvet disease can be stubborn and kill all your fish if not treated in time.

So, put the odds in your favor by following these tips:
  • Keep your aquarium water and accessories pristine
  • Perform regular water analyzes (pH, temperature, filtration)
  • Do not introduce a new fish without having quarantined it for at least 2 weeks
  • Keep an eye on the behavior of your betta fish
  • Observe their physical appearance: fins, tail, gills
  • Don’t overcrowd your aquarium with too many fish

However, it is possible that despite all your good care, your betta will still develop the disease since the parasite may already be present in its body at the time of your purchase. Furthermore, it will attack your poor betta at the first sign of stress from your fish, which is another reason to maintain optimal conditions in its aquatic environment. Also, it is your responsibility to buy betta fish from pet stores where top breeding conditions are respected.

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Final Thoughts

Velvet disease may have a magnificent name, but it can still be fatal to your splendid betta fish. To avoid the painful sight of golden-rusty dead fish floating around in your aquarium, you will need to analyze the water parameters regularly, avoid aquarium overcrowding, provide quality food, avoid stress, follow the procedure for introducing new fish, and maintain rigorous filtration and cleaning of the tank.


Featured Image Credit: ivabalk, Pixabay

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