angelfish velvet disease treatment

How To Treat Velvet Disease in Angelfish

Last Updated on: 19th October 2023, 11:23 am

Velvet disease is caused by a parasite called Piscinoodinium.

When this parasite enters the tank, it searches for a live host to feed off. Fish with velvet disease get eaten from the inside, so they usually die quickly.

Velvet disease is characterized by a gold, velvety film that coats the skin. Other signs include peeling skin, rapid breathing, loss of appetite, and clamped fins.

They also rub against hard surfaces to remove the parasite from the skin.

Effective treatments include a mixture of medication, like copper sulfate, quarantining sick fish, and adding aquarium salt to the water.

Reducing stress also helps to keep the immune system healthy.

What Is Velvet Disease in Angelfish?

Velvet disease, also known as gold dust disease and rust, is an infection caused by the Piscinoodinium parasite. Confusingly, Piscinoodinium is also called the Oödinium parasite.

According to Reviews In Aquaculture, angelfish are infected by free-swimming dinospores with a nail-shaped extension called the rhizoid.

After attaching to the angelfish, the dinospores transform into trophonts, which destroy the cells that feed on the fish’s nutrients.

The dinospores then form a cyst in the angelfish’s natural slime coating and erupt through the skin, dividing into hundreds of tomites that enter the water and begin their search for a host.

If they don’t find one within 48 hours, they die.

Velvet disease is among the most common angelfish diseases. It’s also highly contagious and can affect all fish in the tank if not treated quickly.

Angelfish are also prone to secondary infections from bacteria and fungi, which sometimes lead to death due to the fish’s weakened immune systems.

What Does Velvet Disease Look Like?

Angelfish with velvet disease develop a velvety film that coats the skin. It looks like a golden, green, or rust-colored dust. It most commonly affects the fins and skin but can also afflict the gills.

The velvety coating is caused by excess mucus the immune system generates as a defense mechanism against the parasite. Affected fish may also develop opaque eyes and ulcers on the skin.

Velvet disease isn’t always easy to spot at first, but it can be detected with a beam of light shone directly at the fish in a darkened room.  

One of the most significant issues with velvet disease is that it doesn’t look like a particularly harmful infection, making it hard to detect.

Some owners even buy fish with the disease because they’re mesmerized by the beautiful gold specks that infected fish develop.

what kills velvet in angelfish?

How Long Does Velvet Disease Last?

When free-swimming dinospores are released from a mature cyst, they hunt for a host to live off. Dinospores can survive around seven to eight days without a host. However, when the tank’s temperature is around 75 to 80 degrees, dinospores can live up to 30 days or more.

Once fish become infected, the velvet disease cycle begins. After the parasite coats the fish’s slime, it feeds on the nutrients for 3-6 days. This is the point at which the golden coating appears. After this time, the parasite leaves the body, and the fish dies.  

However, the fish’s death can occur in 12 hours. It can also wipe out the entire aquarium in a matter of days. If fish are already sick or have weak immune systems, the parasite is more likely to kill them quicker than fish with a more robust, healthier immune system.

Therefore, to give your angelfish the best chance of survival against harmful parasites, keep them healthy, and provide stress-free living conditions. Always maintain good tank hygiene, too. Low water quality is one of the leading causes of disease and infection.

What Causes Velvet Disease in Angelfish?

While Piscinoodinium is the leading cause of velvet disease, many other factors contribute.

The disease commonly occurs when a fish infected by the parasite is placed into an aquarium with other fish. As a result, the entire tank becomes infected – many of which die, especially those with the weakest immune systems.

Similarly, if new fish are placed into an aquarium where the parasite is present, it doesn’t take long before the fish become the host. The water must be cleaned before fish are placed into it.

There are also instances when the parasite is already in the aquarium, but it doesn’t affect fish until the tank’s conditions are compromised. Fish with healthy immune systems can sometimes fend the parasite off, but unhygienic conditions make angelfish susceptible to illness.

Signs of Velvet Disease in Angelfish

In the early stages of infection, systems appear minor and may not even show at all. This makes it difficult to diagnose the problem until it’s already too late.

As a result, you must know the signs of velvet disease to spot it early and treat it. Therefore, look out for the following symptoms:

Gold Coating

The gold skin coating is the most noticeable sign of velvet disease.

The coating also looks like rust, which is how the disease gets its colloquial name. The coloration is caused by your fish’s body reacting to the condition, so the color varies between the fish in the tank.

The scales may also appear slimy as angelfish produce extra mucus to remove the parasite. One or both eyes may bulge or cloud over, especially if the water’s conditions are less than ideal.

As mentioned, velvet disease can be difficult to notice because the coloration is sometimes attractive. It can also be subtle unless you shine a light directly onto it.

Peeling Skin

When velvet disease advances, the skin starts to peel from the body. This is where the parasite has consumed the nutrients from the body and destroyed the skin.

Alongside skin detachment, ulcers may appear on the body. This usually happens towards the final stages of the infection when it becomes more severe. Ulcers sometimes detach alongside the skin, leaving bald, red, sore patches of skin.

Rapid Breathing

Stressed fish are more prone to velvet disease. Similarly, velvet disease causes stress.

Distressed fish breathe more rapidly, especially when the parasite attacks the gills. As a result, affected fish struggle to breathe normally and will breathe quickly to get oxygen into the body.

Some fish may head towards the tank’s surface to find more oxygen.

Rubbing Against Objects

Another tell-tale sign of velvet disease is that affected angelfish scratch and rub their bodies across hard surfaces to dislodge the parasites. Experts call this behavior flashing.

As a result, you may find your angelfish rubbing themselves across the sides of the glass and amongst plants for relief. Some fish also dart to the sides or bottom of the tank. They’ll flatten their bodies to touch the substrate.

You might also notice your angelfish twitching suddenly. In extreme cases, they’ll jump out of their tanks, using the surface tension to itch themselves. This is a problem if the angelfish don’t land inside the tank and you’re not around to place them back into the water.

Loss of Appetite

Lethargy and appetite loss are common signs of velvet disease as parasites consume the body from the inside out. This speeds up the process of death. Fish with velvet disease may refuse to eat as the sickness takes hold.

Appetite loss also leads to vitamin deficiencies and other health issues that can make angelfish severely sick. They’re also at risk of long-term illnesses, even if velvet disease is successfully treated. As a result, you’ll need to encourage your angelfish to eat once the condition has gone.

Clamped Fins

Fish with velvet disease clamp their fins against their body, holding them there. They’re not fanned out and become listless. Sometimes, the fins appear torn and damaged.

Alongside this symptom, angelfish may swim without moving forward. This is called “shimmies.” It’s one of the most noticeable signs that your fish have the disease. Once it’s treated, your fish should start moving its fins properly again.

How To Treat Velvet Disease?

Because the parasite detaches once the angelfish dies, you must diagnose velvet disease while the fish is still alive or immediately after death.

Before being diagnosed, the infection is usually in its advanced stages. Therefore, treatment is difficult.

Multiple treatments are usually required when fish are affected by velvet disease. This is because the parasites may be in different life cycles and require different levels of treatment. 

As mentioned, you’ll need to act fast to save your fish once infected. To do so, these are some of the best treatments for velvet disease:

Aquarium Salt

Treating velvet disease with fish salt is an effective way to clear up velvet disease. Immerse the fish for prolonged periods in non-iodized table salt to dislodge the trophonts from the fish.

Make sure you administer the right amount, though. Dissolve the salt in 0.5 to 1 gallon of warm water. Add 2.5 teaspoons of aquarium salt for every gallon of water in the tank.

Similarly, short periods of hyposalinity or osmotic shock is another effective way to treat velvet disease in angelfish, as it removes trophonts from the skin and gills.

Whichever treatment you try, transfer the angelfish to a clean environment and repeat the process several times, ensuring the fish has a few days of recovery between each treatment.


Affected fish must be quarantined from the rest of the tank to prevent the fish from becoming sick. Keep fish in the tank for three weeks at 82 to 86°F. Raising the water’s temperature speeds up the parasite’s life cycle, making treatment faster and more effective.

Also, cover the tank with a blanket. Velvet disease-causing parasites have chlorophyll in their cells, which means they use photosynthesis and light to survive. Blocking out the light helps kill the parasites more quickly.

During the quarantine process, keep infected fish away from healthy fish for as long as it takes for the parasite to die. If you put the fish back into the main tank too early, it could carry the parasite, starting the infection again.

Regarding the tank’s size, 10 to 20 gallons is usually sufficient. It might also help fish feel less stressed by adding plants and replicating the look and feel of the main tank.


Medication is needed alongside other treatments to get rid of velvet disease completely. A few effective medications are available – the one you choose depends on the drug you’re most comfortable using.

When administering any medication to the aquarium, remove activated carbon from the filter because it’ll remove the drugs from the water.

One of the most commonly used medications for velvet disease is copper sulfate. It’s a chemical that successfully kills various parasitic, bacterial, and fungal infections. 

However, as Science Direct warns, many fish are sensitive to copper. Some become intoxicated at concentrations required to control pathogens, so use copper sulfate cautiously.

Don’t use copper if the pH is too low. Anything below 6.4 is toxic and will kill the angelfish. Also, only use copper sulfate in a quarantine tank where no plants or other living matter is present. It’s best only to add copper sulfate to your treatment tank. Other effective medications include:

  • Mepacrine.
  • Formalin.
  • Methylene blue.

Reduce Stress Levels

Chronic stress leads to a weakened immune system, which makes angelfish susceptible to velvet disease. Reducing your angelfish’s stress levels helps to make them less vulnerable to infections.

Many factors increase stress levels, including:

  • Tank overcrowding.
  • Aggressive fish.
  • Lack of food.
  • Poor nutrition.
  • Poor tank hygiene.
  • Environmental noise.

Stressed fish are more prone to picking up diseases, so stress must be minimized to keep fish healthy for as long as possible.

Provides Vitamins

Vitamins are another effective way to boost the immune system, strengthening it against harmful parasites like the velvet disease-causing pathogens.

Feed your angelfish vitamin C and E supplements to ensure appropriate vitamin levels. You can find liquid vitamins in aquarium stores that provide concentrated levels and other natural nutrients to keep your fish healthy.

Similarly, adding prebiotics, probiotics, postbiotics, parabiotics, and symbiotics to your fish’s diet can positively affect the immune system, helping it grow and become stronger. 

How To Prevent Velvet Disease

Velvet disease kills quickly and affects the entire aquarium without warning. You’ll lose everything inside the tank if you don’t catch and treat it fast enough.

As a result, you can prevent the disease by following these methods:

gold dust disease

Maintain Water Quality

To keep fish healthy and their immune systems strong, you must maintain the tank’s water quality to an acceptable level. Low water quality leaves your angelfish susceptible to pathogens and bacteria, including velvet disease-causing parasites.

Murky water, chemical imbalances, or thick algae encourage harmful bacteria to grow. Other factors that affect water quality include:

  • Decaying organic matter.
  • Too many fish.
  • Unchanged water.
  • Excess feces.
  • Clogged filter system.

Regular testing is required to regulate the pH levels to ensure good water quality. Testing also shows when harmful ammonia and nitrites are present, which causes bad bacteria to grow and also makes fish extremely unwell. When cleaning your angelfish tank:

  1. Replace the tank’s existing water with 10% to 20% fresh water.
  2. Thoroughly scrub the sides of the tank to remove algae and build-up of harmful bacteria.
  3. Dechlorinate the water before adding it to the tank.
  4. Remove all decaying matter from the tank, including dead angelfish, rotting plants, and old food.
  5. Clean out the substrate using a siphon to remove decaying matter.
  6. Remove gunk and slime from the tank’s filter by running it through the tank’s water. This will preserve the beneficial bacteria.

Repeat the process every other week to maintain your tank’s hygiene levels and protect your angelfish against harmful conditions like velvet disease.

Provide A Healthy Diet

As mentioned, vitamins and minerals are essential for your angelfish’s health. Angelfish get all the nutrition they need from a balanced, high-quality diet, so make sure you’re feeding your angelfish with premium food.

Similarly, feed your fish the right amount. Angelfish should be able to eat for 30 seconds without stopping. Any more is probably too much, and any less is not enough.

Fish who undereat are at risk of malnutrition and won’t get the vitamins and nutrients they need to stay healthy. Some fish are at risk of undereating because of aggressive fish who take all the food. Suitable angelfish foods include:

  • High-quality angelfish flakes.
  • Frozen food, such as brine shrimp, bloodworms, and Mysis shrimp.
  • Freeze-dried foods.
  • Occasional live food that angelfish can hunt.
  • Vegetables, such as blanched peas, cucumber, and zucchini.

These provide your angelfish with all the nutrients they need to thrive.

Quarantine New Fish

Before placing new fish into your existing fish tank, quarantine them for around 2-4 weeks.

Many owners consider quarantine tanks expensive, but they save time and money. They can also double up as a treatment tank in cases of infection and disease, like velvet or coral disease. Because of this misconception, naïve fish openers add new pets into the tank.

Some fish harbor Piscinoodinium while in their original aquarium. When placed into a new one, they infect the rest of the tank and cause all fish to pick up velvet disease. Quarantining prevents this. 

During quarantine, monitor the fish for any signs of illness and disease. Angelfish infected with velvet disease may experience a change in scale color. 

Velvet disease is a condition most owners dread. It’s difficult to detect and hard to treat. The parasites aren’t usually seen until placed under a microscope – at which point, the disease is usually too late to treat.

Once the Piscinoodinium enters the tank, it will look for live hosts to feed off. Don’t risk it. Keep the tank clean and provide a nutritionally dense diet.