Velvet is a parasitic infection that attacks the skin cells of fish. The parasites appear on the fish as rusty-gold flecks. The tricky thing about these parasites is that they have three life stages. Medication does not affect them when they are visible, feeding on the fish’s skin. They are only treatable during their free-swimming phase when they are invisible.
Fortunately, velvet is highly treatable when it’s caught early. Medication is often unnecessary.
Aquarists can use aquarium salt, warm temperatures, and darkness to kill the parasites.
More severe infections need medication to kill the parasites.
What Is Velvet?
Velvet is a type of parasite from the Oödinium genus that is highly contagious.
It is like marine velvet that occurs in saltwater aquarium fish. The difference between the infections is the organisms that cause the infection.
Several species of Oödinium dinoflagellates infect freshwater fish.
Dinoflagellates called Amyloodinium ocellatum infect saltwater fish.
Dinoflagellates are single-celled algae that have two flagella. Flagella are thin, string-like appendages that help the parasites swim.
Velvet are ectoparasites that attack the fish’s slime coat and eat at the cells. These single-celled organisms are a rusty-golden color. Their color is why the infection is sometimes called “gold dust disease.”
The Life Cycle Of The Oödinium Parasite
Like ich, the parasites that cause velvet have three stages in their life cycle.
Dinospore (Free-Swimming Stage)
These parasites begin their lives as dinospores capable of free-swimming. They move from the bottom of the aquarium to the water column, where they search for a host.
Trophont (Feeding Stage)
Trophont parasites penetrate the betta’s slime coat, which protects the parasite.
It forms a hard shell, called a cyst, around its body to defend itself. The cyst appears as gold flecks on the fish’s skin.
Once the parasite is inside the betta’s slime coat, it eats at the fish’s cells.
After a few days of feeding, the cyst falls from the fish’s body to the bottom of the aquarium.
Tomont (Reproduction Stage)
As a tomont, the parasite attaches itself to decorations or gravel in the aquarium.
It begins reproducing through mitosis, a way in which the cell divides itself. The cell divides into over 200 identical cells.
The Causes Of Velvet
Poor water conditions and improper quarantine of new organisms usually cause velvet.
New Fish & Plants
Quarantine is the best way to prevent the whole aquarium from getting sick.
Aquarists should always quarantine new fish, inverts, and plants before putting them in the main tank. They may have an illness or infection that the hobbyist doesn’t notice right away.
Fish, inverts, and plants should stay in a smaller quarantine tank for about four to six weeks. That time allows the hobbyist to see if there are any problems and enables them to address them.
Poor Water Conditions
Stress and sickness are common in poor environments. High levels of ammonia, nitrites, and nitrates are toxic. The wrong pH or temperature can also have ill effects.
Parasites often live in healthy fish tanks without hobbyists ever realizing it.
While the fish are healthy, their immune system helps them fight off the parasites.
Fish experiencing stress or sickness are far more likely to develop an infection. Their immune system is weak, making them easy prey for the parasites.
Neglecting Water Changes
Hobbyists that don’t do routine water changes help parasites to repeatedly reproduce.
Doing routine water changes is essential for getting rid of parasites at all life stages.
Regular water changes may not get rid of every parasite. They will keep their populations under control so they are less likely to infect fish.
Sudden Changes
Rapid changes in the water parameters cause shock. Shock makes fish more susceptible to infection.
Keep the tank as stable as possible. Avoid quick changes in pH and temperature.
Velvet Symptoms
The primary symptom of a velvet infection is the rusty-gold spots on the fish’s body.
Unfortunately, these spots are often difficult to see with the naked eye.
Many hobbyists notice other symptoms first. Suspecting velvet, they hold a bright flashlight to the fish to see if they have any gold spots.
Early Warning Signs
The first thing that hobbyists usually notice is their betta acting differently. They become more lethargic and may lie around the tank. Their appetite decreases, and they may become thin from not eating.
The rusty-gold specks appear on the fish at this stage. Their normal color fades, and they appear pale.
Bettas often begin rubbing their bodies against decorations to relieve itching. Rubbing may cause tears on their bodies and fins.
Late-Stage Symptoms
It’s challenging to treat bettas once their velvet infection becomes more severe.
Common late-stage symptoms include:
- Cloudy eyes
- Clamped fins
- Eye protrusion*
- Sloughing skin
- Ulcers on the skin
Ulcers and skin sloughing occur because the parasite burrows further into the skin. The parasites destroy the skin cells as they burrow.
They can also develop as injuries from the betta rubbing themselves against decorations.
* A betta’s eyes may begin protruding from their sockets due to fluid buildup in the area behind the eye. Such protrusion is different from popeye.
How Fatal Is Velvet?
Velvet is treatable and doesn’t need to be fatal if hobbyists catch it soon enough. The longer the infection goes untreated, the more likely the fish will die.
Is Velvet Contagious?
Velvet is incredibly contagious. Hobbyists must separate sick fish from healthy ones and begin treatment immediately.
How To Prevent Velvet
It’s generally easy to prevent velvet by providing the betta with a suitable environment.
Keep the tank healthy and quarantine all new organisms and plants. Never add new fish or plants directly to the main tank.
Ensure that the betta is receiving a nutritionally-complete diet.
Test & Clean The Water
Test the water regularly — at least once a week. Perform routine water changes with a gravel vacuum to remove waste.
Check the thermometer to ensure the water temperature is within a healthy range for a betta.
Don’t overfeed or overstock the tank.
Quarantine New Fish, Invertebrates, & Plants
Quarantine all new fish, invertebrates, and plants for three to four weeks. Only add them to the main aquarium if they show no signs of sickness.
Treat sick fish and invertebrates to get them healthy before putting them in the main tank.
Disinfect plants to kill parasites and bacteria before adding them.
Feed Healthy Foods
Betta fish are obligate carnivores that need a meat-based, protein-rich diet.
Don’t make the mistake of feeding bettas tropical fish food, as it doesn’t contain enough protein.
Bettas should receive a variety of healthy pellets or flakes and live or frozen food.
Hobbyists worried about parasites should avoid live food. Though it’s not super common, fish sometimes develop parasites from their live food.
How To Treat Velvet
There are three primary steps that hobbyists must take to treat velvet:
- Raising the temperature
- Keeping the tank dark
- Use aquarium salt
Fortunately, velvet is easy to treat when caught in its early stages. Treatment becomes considerably more tricky once the infection progresses.
Increase The Temperature
Raising the temperature in the tank is vital. Velvet parasites cannot survive in warmer temperatures.
Ideally, raise the temperature to between 82-86°F (27.8-30°C).
Don’t raise the temperature too quickly. Drastic temperature changes shock fish and can cause death. Gradually raise the temperature by 1-2° a day, never more.
Mix Aquarium Salt Into The Water
Aquarium salt is excellent for healing sick and injured fish.
Dissolve the salt in water and slowly add it to the tank. Follow the instructions on the package to know how much to add.
Hobbyists should ensure they use aquarium salt, not table salt or sea salt.
Cover The Tank With A Blanket
One of the best ways to kill off velvet is by keeping the tank dark. The easiest way to keep a tank dark is to wrap it in a blanket.
Velvet is a type of algae — it needs light to photosynthesize and produce energy. Without light, it can’t survive.
Aquarists can move small tanks into a hardly-used room. Keep the room dark by keeping the lights off, and the curtains closed.
Other Ways To Treat Velvet
There are other things hobbyists can do to help the process. Quarantine sick fish, keep the tank clean, and use medications to speed up healing.
Don’t skip the three steps above as they are the most critical in treating velvet.
Quarantine Sick Fish
A sick betta that usually lives in an aquarium with other fish should move to a quarantine tank.
Move other ill fish to the quarantine tank as well; leave healthy fish in the main tank.
A betta that lives in a tank alone can stay in their tank for treatment. Sometimes, it is less stressful for them to remain in their home tank.
Aquarists may need to move bettas with trouble swimming to a smaller quarantine tank. Moving may be necessary if their home tank exceeds five gallons.
Keep the water level shallower than usual. Shallow water makes it easier for the betta to surface to breathe.
An Empty Main Tank
Sometimes, treating a betta in a hospital tank is easier, even if it has no other tank mates.
Once free-swimming, the parasites must find a fish for a host. Parasites that can’t find a host will die after a few days.
The infestation inside the tank will die out by leaving the main tank empty for a week or two. The tank will be safe for the betta to live in after healing.
Test The Water
With a sick fish, testing the water is more important than ever.
Testing tells hobbyists whether their tank is safe. Tanks with high ammonia, nitrites, or nitrates may have caused the infection. Tanks with the wrong temperature or pH can also cause infections.
Clean The Tank
Perform daily water changes of about 50% during treatment. Doing so helps remove many of the parasites in the water. It reduces their current populations and makes it harder for them to reproduce.
Use Medications
Medications to treat velvet can be harsh and stressful for fish. Most hobbyists save medications for severe cases.
Start by trying aquarium salt, darkness, and temperature increases.
Medications are only effective during the dinospore, or free-swimming, phase. They will not work during the tomont or trophont stages.
NEVER stop medication early — humans can’t see dinospores can’t with the naked eye. The parasites are still there, even when we can’t see them. Stopping medication early prevents the medication from killing them.
Copper-Based Medications
Copper sulfate is highly effective but can be more difficult to use.
Chelated copper is easier to use, especially for beginners, though it’s less effective.
Always read the directions on the label and follow the instructions precisely. Using the medication wrong will prevent the parasites from dying.
Copper-based medications are toxic to invertebrates, scaleless fish (like loaches), and plants. Never use this medication with these organisms, or they will die.
Never use copper-based medications in tanks with a low pH. Copper becomes highly toxic in water with a pH lower than 6.4 because it kills the beneficial bacteria in the tank.
Malachite Green
Malachite green is another effective medication to use against velvet. Only use malachite green in quarantine tanks because it can stain decorations.
How Long Does Treatment Take?
Hobbyists will want to treat their infected fish for about three to four weeks. Medications are only effective during one stage of the parasite’s life.
A parasite that can’t find a host will die within two days. Those who find a host can live for several weeks and reproduce rapidly.
FAQs
Why Does Velvet Keep Coming Back?
Velvet will keep returning if it’s not treated correctly. The parasites have three life stages. Medication is only effective during one of those stages.
Aquarists often stop treatment early because they no longer see the parasites. Unfortunately, free-swimming velvet parasites are not visible to the naked eye. Most hobbyists stop treatment when it’s most important.
What if hobbyists aren’t using medication? They may not be keeping the tank dark or warm enough.
It may be time to try medication, as the infection is likely severe.
How Long Can A Betta Fish Live With Velvet?
Bettas will usually live a few weeks with velvet if they don’t receive treatment. How long they survive depends on how quickly the infection progresses.
Does BettaFix Help Velvet?
Avoid API products that end in “fix,” like BettaFix and MelaFix, when treating bettas. While these medications can be helpful for other species, they are often fatal for bettas.
These products comprise melaleuca (tea tree) oil that sits on the water’s surface.
Bettas come to the surface for air, ingesting the tea tree oil as they do so. The oil coats their labyrinth organ and can suffocate them if they consume too much.
