Betta Fish Velvet Disease: Symptoms & Causes (+Treatment)

Velvet in Betta Fish
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Last Updated: June 17, 2023 by Dave Gibbins

As fish enthusiasts, we try to provide the best care for our pets. Maintaining your Betta’s health includes preventing, diagnosing, and treating health problems. One such disease is Betta Velvet, spread by Oödinium in your freshwater aquarium.

Betta Velvet can spread between your fish or from one aquarium to another. That makes it necessary to identify the problem before it spreads everywhere.

Like most health problems you will encounter in the hobby, Velvet or Gold Dust disease is easy to treat when detected early instead of later in the disease cycle.

We provide the information that follows to help you understand Velvet disease and identify steps you can take to prevent and treat it.

What Is Velvet Disease?

Velvet disease (also called Coral disease, Gold Dust disease, or Rust disease) is a fish disease caused by small parasites in your Betta tank. These single-celled organisms penetrate a Siamese Fighting fish’s slime coat and begin to eat at its cells. It has been found in marine tanks but affects freshwater aquariums more often.

Betta Fish Velvet Disease : Symptoms, Cause and Treatment -

What parasite causes Betta Velvet?

There are two major types of algae (dinoflagellate) that can develop the disease. Amyloodinium ocellatum live in brackish or seawater conditions. Betta Velvet comes from Oödinium (several species exist and can affect fresh or saltwater fish).

The single-celled organism that causes Betta fish Velvet has a three-stage lifecycle:

  • Tomont
  • Juvenile
  • Adolescent

The Oödinium parasite begins the first life stage as a single cell organism resting upon decorations or substrate in your Betta fish’s tank. It reproduces by fission, dividing into an identical cell. Each organism can divide into 256 individual Oödinium tomites, helping to explain how quickly the algae grows.

As each organism matures, they become juveniles capable of motility. Their independent movement allows them to move from the floor of your tank and into the water column. Betta with Velvet becomes a host as the parasites attach to them.

Adolescent parasites that locate a host can enter a Betta fish’s slime coat. That coating acts as a protective layer, so once penetrated, your Siamese Fighting fish is vulnerable to the parasite’s consumption of cells (Gold Dust disease).

Can Velvet disease come from bacteria or a virus?


Betta Velvet stems from a parasite infestation. That influences how they attack a host, what cells it targets, and how to treat the disease.

Viruses require a host to reproduce. The algae that cause Betta with Velvet divides and replicates itself outside of the host. Viruses also target specific cells, while Betta Velvet attacks a broader range of cell types.

Parasites, including the one that causes Betta Velvet, are structurally more complex. For you, this means that it cannot live as long without a host as bacteria can. Established bacteria colonies can last indefinitely without proper treatment.

What Are The Symptoms Of Betta Velvet?

As a Betta keeper, you will need to know what to look for so that you can keep your pets healthy and happy. Fortunately, Betta Velvet produces symptoms that you can observe. That will allow you to treat the Velvet disease before it becomes fatal.

Betta fish Velvet symptoms can appear as:

  • A loss of color
  • Development of rust/yellow film

One change that Betta fish Velvet produces is a loss of color. For obvious reasons, this is more noticeable on male Betta fish than on females that tend to be more muted in color. Male Betta with Velvet can maintain color patterns, but they are not as vibrant as when your fish was healthy.

Another color change comes in the form of a film or spots that build upon the skin surface. It can be rust in color (hence, the name Rust disease) or yellow. These spots or film layers can develop anywhere on your pet’s body.

Gold Dust disease can appear as either symptom or as a combination of both.

Physical changes caused by Betta Velvet can include:

  • Clamped fins
  • Labored breathing
  • Peeling skin

A telltale sign that your Siamese Fighting fish is not feeling well is a clamped fin. Ventral fins will be parallel with the body, while the anal and dorsal fins will be closed. The caudal (tail) fin will be partially open but noticeably smaller than usual.

Betta with Velvet often displays labored breathing. The gills move more quickly than under normal conditions. Your Siamese Fighting fish will appear to be struggling as it breathes, and those labored breaths will come at odd rhythms.

Once the Velvet disease begins to advance, you might see your pet’s skin begin to fall off. That indicates that your Betta is very ill and might pass away without immediate care. Often, a fish is beyond simple treatments, and you should consult with an experienced keeper or a veterinarian.

Velvet also causes aberrations in your betta fish’s behavior, including:

  • Less active
  • Loss of appetite
  • Scratching

Betta Velvet can cause your fish to become lethargic. You will notice it does not move around the aquarium and tends to stay put, often hiding.

Another sign of Velvet disease is a fish that will not eat. Fish that lose their appetite become weaker as they have less food to convert into nutrients for energy and fighting sickness.

Gold Dust disease agitates your fish’s skin. That makes your Betta seek relief by scratching against decorations and substrate in the fish tank.

How Can You Prevent Betta Velvet?

Betta Velvet is highly contagious, and it can be hard to treat once your Betta’s home is infected. Your best bet is to prevent Betta fish Velvet from contaminating your aquarium. Some things you can do to prevent many diseases, including Gold Dust, from entering your fish tank include:

  • Quarantine new fish
  • Frequent water changes
  • Water testing
  • Don’t overcrowd
  • Feed properly

Betta Velvet is often introduced into an aquarium by contaminated fish. If you add Betta with Velvet, they will infect the water column and other tank mates. Quarantine new fish for two weeks before adding them to your fish tank (infected fish will display symptoms before this period expires).

Frequent water changes prevent build-ups of unhealthy contaminants like Betta Velvet. Regular water changes will introduce fresh water into the water column, keeping your fish’s environment clean.

Good water quality is necessary to prevent many fish diseases, including Gold Dust disease. A good water testing kit will allow you to examine several parameters like PH, ammonia, nitrate, nitrate, among other things. You can adjust the water conditions to keep your Betta healthy, such as water at a neutral 7.0 PH.

Overcrowding is usually not an issue for most Betta tanks as most keepers know they like their space. If you house your Betta fish in a community tank, make sure not to put too many fish in the aquarium. Lots of fish will keep your Siamese Fighting fish stressed, and that stress makes them vulnerable to things like Velvet disease.

Betta fish Velvet thrives in poor tank conditions, including environments polluted with excess food. Make sure to feed just enough food that your pet can eat in just a couple of minutes. Feeding them a healthy diet with more nutrients than filler will also help prevent Betta Velvet from affecting your fish.

How Do You Treat Betta Velvet?

If your preventative measures do not work and your Siamese Fighting fish displays Betta Velvet symptoms, there are several methods to treat it. You can try one or more of these non-medicinal methods to help eliminate Velvet disease:

  • Water change
  • Increase water temperature
  • Decrease light

A large water change will clean out many of the parasites suspended in the water column. The method targets the organisms in their tomont and juvenile stages before they infect your Betta fish. It also eliminates pollutants that reduce your pet’s ability to fight Betta Velvet.

Raising your betta’s water temperature can also help eliminate Gold Dust disease. Betta fish do best in water heated between 74 and 79-degrees Fahrenheit. Increasing the temperature slowly over 24 hours until it reaches 84-degrees will shorten the parasite’s lifespan.

The organisms that infect Betta with Velvet require light. Leaving the tank in the dark for seven days will starve the algae in the water. It will not affect the Gold Dust disease already affecting your pets, but it will help reduce the juvenile parasites.

These treatments work well when combined. They also act well when combined with chemical treatments like:

Salt promotes the production of the fish slime that helps to protect your pets from Gold Dust disease. Adding between one and three teaspoons of aquarium salt per gallon of water can help fish that are not displaying symptoms. It can also help with healing after other treatments on fish infected with Velvet disease.

Copper sulfate is a longtime method for treating Gold Dust disease. A full treatment will last for 10-days. You will need to follow the manufacturer’s suggested dosage and schedule for effective and safe results.

Many products are available that target Betta Velvet. Quinacrine hydrochloride and other compounds can be added, with varying results. Specialty products, like API’s Bettafix line, will treat and repair fins and scales.

When you use treatments in your aquarium, make sure to remove the carbon from your filter system. Carbon will absorb your medicines, reducing their effectiveness or eliminating them from the water column completely.

API Bettafix Betta Medication - 1.7 oz (93B)
  • All natural
  • Betta medication
  • Heals damaged fins and skin
API AQUARIUM SALT Freshwater Aquarium Salt 33-Ounce Box
  • Contains one (1) API AQUARIUM SALT Freshwater Aquarium Salt 33-Ounce Box
  • Promotes fish health and disease recovery with increased electrolytes
  • Improves respiration for fish in freshwater aquariums
  • Made from evaporated sea water for all-natural results
  • Use when changing water, when setting up a new freshwater aquarium and when treating fish disease

Betta Velvet Does Not Have To Be Fatal

Betta Velvet is not a bacteria or virus, but it is a single-celled Oödinium (algae) that can infest the water in your tank. Understanding its pathology will help to prevent and treat it early.

The sooner that you treat Velvet, the more likely your favorite Siamese Fighting fish will survive.

Do you still have questions about Betta Velvet or other diseases? Make sure to ask them below so we can help you enjoy your hobby to the fullest!

Betta Velvet checklist

  • Prevent parasites – Quarantine new fish, change and test water, don’t overcrowd or overfeed
  • Identify symptoms early – This includes color changes, clasped fins, rapid breathing, and scratching, among others
  • Treat as soon as possible – Eliminate light, raise the water temperature, add aquarium salt, and treat with medications (like Bettafix)
Betta Fish Velvet Disease : Symptoms, Cause and Treatment -

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