Marine Velvet – Surviving and Preventing A Tank Terror

Thank you for visiting! By the way… any links on this page that lead to products on Amazon and other stores/partners are affiliate links. Aquarium Store Depot earns a commission if you make a purchase.

Have you come to this post wondering if your fish has Marine Velvet? I feel your pain if you have. In my over 25 years of experience, Marine Velvet is the most common disease tank crasher in the hobby. It strikes fast, kills fast, and most people aren’t prepared for it. It’s the one disease I fear the most in my saltwater aquarium. In fact, it is labeled one of the deadly three in my how-to quarantine saltwater fish post.

In this post, I will go through everything you need to know to fight this deadly disease. You will learn what it is, its life cycle, how to treat it, and how to prevent it. It is a true tank terror and I’m not going to sugarcoat it. If your tank has it right now, chances are one or more of your marine fish will succumb to this disease. Let’s get started on what you need to know first.

What You Need To Know (The Facts)

NameAmyloodinium ocellatum
Common TreatmentsChloroquine Phosphate or Copper
Short-Term TreatmentAcriflavine or Formalin bath
CausesTransferred from infected fish, corals, or water
Fallow Period6 weeks
Common SymptomsNumerous white dots on the body, fins, flashing, swimming to flow of wavemakers, erratic swimming behavior

What is Marine Velvet? (Amyloodinium ocellatum)

Marine Velvet Disease, scientifically known as Amyloodinium ocellatum is a dinoflagellate (not the same brown stuff mentioned in my other post). It is well known for killing prized saltwater fish in less than 24 hours, and it spreads the most during the warmest months of the year in the aquarium trade. If you are well versed in the hobby, you will often hear of increased cases of this disease during the summer. It makes summer one of the riskiest times to purchase fish locally or online.

Because it is a dinoflagellate, it has unique features compared to other diseases in our hobby. It is often mistaken as ich (Cryptocaryon irritans), and because of this, you should learn the differences between the two.

Marine Velvet vs Ich – The 4 Key Differences

It’s very easy to confuse these two diseases. I’ve heard many folks say, “ich wiped my tank.” However, their stories, of how quickly everything happened, made me suspect it was actually Velvet. Let’s go into the four main differences so you know what you are tackling. They are:

  1. The number of spots
  2. Type of free swimmers
  3. Life cycle
  4. Time of infection

1. The Number of Spots

Your first indicator is usually the number of spots. Ich’s white spots are spread out and easy to count. With Velvet, the spots are so numerous it’s difficult to count them all. It’s almost as if the fish was dusted with white power (source). You can see an example of both diseases below. Note how the purple tang has spots spread out while the Achilles tang has spots all over its body, including the eyes.

2. Type Of Free Swimmers

Because Marine Velvet disease is a dinoflagellate, the free swimmers are called velvet dinospores, while ich’s are called theronts. While this is a technical term, one thing to know is that dinoflagellates feed off sunlight which makes it susceptible to blackouts, UV, and Ozone – though once you have an outbreak you will need to take more extreme measures to fight it off. All of these will control the spread, but will not cure an already infected fish!

3. Life Cycle

Velvet averages a 4-day life cycle and there are more attacking free swimmers than ich. This is why they can overwhelm and kill fish so fast. Ich’s life cycle can be as long as 2 weeks.

4. Time Of Infection

Because Velvet is a dino, it remains infective for up to 15 days. This is because as dinos, they can feed off sunlight. Ich is only infectious for up to 48 hours. The fact that it remains infective longer and attacks in larger numbers and longer is what makes this disease far deadlier than ich.

Marine Velvet Life Cycle

As I mentioned before, the life cycle is only 4 days and starts when a Velvet dinospore attaches to a fish’s skin. The attached velvet dinospores are then called trophonts. This trophont will feed on your fish for several days before detaching. Sometimes, the trophonts are so numerous and overwhelming that it will kill the fish before it shows any symptoms.

Once the trophont detaches, it is called a tomont. These tomonts divide until they burst. When they burst, they become new velvet dinospores. These dinospores then attach to a new host, starting the lifecycle all over again.

Let’s illustrate this lifecycle with an image. The image below is from Dr. Fish himself, Humblefish. He is the go-to for all marine fish diseases in our hobby. Check out his site for further info on all other saltwater ailments and treatments.

Marine Velvet Life Cycle

Marine Velvet Treatment (How To Cure)

Marine Velvet disease needs to be treated ASAP. You need to treat it in a quarantine tank as all effective medications against it are not suitable to be used in reef tanks. There are several steps you will need to take:

  • Get the proper medication
  • Get a test kit
  • Set up a quarantine tank
  • Perform short-term relief procedures
  • Perform treatment procedures

1. Get The Proper Medication

Step number 1 here. The preferred treatment option for Velvet is chloroquine phosphate. Unfortunately, due to the COVID-19 pandemic and its mass usage for treating malaria1 , it is getting difficult to find. Even with a vet, most are now reluctant to prescribe it to a hobbyist. Chloroquine phosphate is highly effective and can be used with no ramp-up time. However, given its lack of availability, it will not be your primary treatment option.

Copper is your new go-to treatment option. We will need to do some additional steps to make it work against Velvet. There are two types of copper: ionic and chelated. Ionic copper is what you will find in most fish stores due to the availability of SeaChem Cupramine. It has a shorter range of therapeutic levels (0.4 – 0.5 mg/L) and degrades fast. It’s not my preferred choice.

Chelated copper is stable and has a larger range of therapeutic levels. Fish are more tolerant to it than ionic copper, and it is generally more effective against diseases than ionic copper. My preferred choice for chelated copper is Copper Power by Endich. Make sure you get the blue version, as there is a green version that is exclusive to freshwater Velvet. The effective range for chelated copper is 1.5 to 2.0 PPM. If you want research-backed info of copper medications – see this write-up from the University of Florida (UF is also the source of my featured image).

Unfortunately, most stores will not have Copper Power in stock. Amazon Prime is your best bet for fast delivery. If you are researching this article and do not have a fish that is sick, I would purchase some now. It has a long shelf life.

2. Get A Test Kit

If you manage to get your hands on chloroquine phosphate, you are in luck. You do not have to use a test kit for CP because there is none available to the hobbyist. Only lab-grade equipment can test for CP and that is way out of the price range of most people, and also not available to purchase unless you are a lab tech.

If you get copper, you will need a test kit. There are many factors with copper that call for a test kit. For one, copper gets absorbed by lots of things in your aquarium – your filter, the silicone in your aquarium, and any decorations. This is why hospital tanks are set up with PVC piping and simple power filters or sponge filters.

Of all copper test kits available, the best out there is the Hanna Checker

3. Set Up A Quarantine Tank

A proper quarantine (AKA hospital tank) is a must. You will need to remove all fish from your display tank as the disease will need to be starved out of your display. More on this later when I explain the fallow period. Depending on the number and size of fish, most people will be working with a 10, 20L, or 55-gallon tank when treating for Marine Velvet disease. I prefer the 20L gallon since it is a nice combo of size, space, and cost-effectiveness. A 55-gallon tank is used for large or multiple fish. Ammonia levels should be monitored with a SeaChem Ammonia Alert Badge.

For the full setup you will need:

I walk you through the part selection below in my video. I bookmarked it to the section where I go through each piece of equipment.

The main concern with a hospital tank is not having a bacteria culture to jumpstart it. If you have media in your display tank, move it over to the hospital tank to seed the tank. I would also recommend using Bio-Spera. This is my preferred choice for bacteria in a bottle for hospital tanks because you can find it everywhere – even in chain pet stores.

4. Perform Short-Term Relief Procedures

Because most of you will need to use copper to treat Marine Velvet disease, you will need to perform short-term relief procedures to give your fish relief from the disease. To do so, we will want to use an Acriflavine or Formalin bath. Since Formalin is a controversial medication and even banned in some states, Acriflavine is going to be our best choice.

There is actually one product in our hobby that contains both Acrifalvine and Formalin, That product would be Ruby Reef Rally. This is the preferred solution for providing relief to our fish. Here are the steps:

  • Prepare a 2.5 gallon or 5 gallon bucket depending on your fish size with a heater and air pump
  • Put your display tank water into the bucket
  • Add the recommended dosage of Ruby Reef Rally to the bucket and mix fully
  • Place fish into the bucket and allow 90 minutes to observe for signs of stress
  • Remove fish and place it into your hospital tank – start the next relief procedures

Ruby Reef Rally is my go to for dips. I use it for disease relief and also before I introduce any fish into my quarantine tanks. It is available at most local fish stores.

If you are unable to procure Rally, you can do a 5-minute freshwater dip. Walking through a freshwater dip can be a separate article in itself. Here is a video from Meredith Presley to get you going. She does this for gill flukes, but a freshwater dip is an effective short-term option for Marine Velvet disease.

5. Perform Treatment Procedures

It’s time to attack this disease full-on. Since there are two ways to tackle this beast, I’ll walk you through both.

Treating With Chloroquine Phosphate

If you are fortunate to get this wonder drug, here is how you eradicate Velvet with it:

  • The typical dosage is 40mg per gallon
  • Use a digital scale when measuring your dosage
  • Use your hospital tank water in a cup to pre-dissolve the solution
  • For Velvet – you will need to maintain 40 mg per gallon for a minimum 14 days to treat – 30 days is preferred
  • If a water change is done, you must replace the water with medicated water using the same 40mg per gallon dosage
  • To top off water, you will not need to add medication

I provided my video again, this time at the 7:00 mark where I walk you through how I mix CP in my quarantine tanks. You can see how I use the digital scale to measure, how I pre-dissolve, and how I add it to the aquarium.

Treating With Copper

Copper is a bit tricky because we have to work with the ramp up time. Most fish cannot tolerate an instant ramp up to therapeutic ranges. This is why we need to perform those short term procedures I explained previously to buy us time. We will need to perform a 24-hour ramp up. Here are the steps to getting us to effective levels:

  • Start off by raising copper levels to 1.0 ppm – verify with your Hanna Checker
  • Over the next 24 hours – raise your levels to 1.5 ppm. Do this every 8 hours, raising 0.125 PPM each time
  • After you raise it to 1.5 ppm – bring it to 2.0 ppm over the next 24 hours. Do this every 8 hours, raising 0.125 PPM each time
  • Treat for 30 days keeping levels above 1.50 ppm. If you drop below 1.50 at any time, your countdown to 30 days starts over!

The Marine Velvet Fallow Period – How to Eradicate The Disease In Your Display Tank

Treating the disease in the hospital tank and saving your fish is the first battle we fight. Completely eradicating Velvet from your display is how to get a total victory. To do this, we must understand the fallow period needed to wipe it out. I also need to explain what fallow means.

Fallow means no fish in your display. Velvet needs the fish as a host, without the fish, the disease starves out and can’t reproduce. Any coral inverts, and clean-up crew you have in your display can stay in your tank. This can be really discouraging for a reefer to have a fishless tank. There have been times that I have recommended to a hobbyist to impulse buy corals when at the beginning of the fallow period. Just buy a bunch now.

Why would I say that? Because after you place all those corals you always wanted, you can begin your fallow period. It’s something you can look forward to. When your fish return they will be treated to new corals and structures to explore in a disease-free tank! The fallow period is also a long time.

How long is it? The fallow period needed to completely wipe out Velvet from a display tank is 76 days. Yes, I know that is a long time. Now you see why I’m suggesting you go buy those corals you always wanted now where there is no risk to spread disease to your fish!

During this time, you must make sure you do not cross-contaminate your tanks. Keep your hospital tank 10 feet away from your display tank and use separate nets, buckets, and equipment. Make sure you wash your hands before switching tanks with a reef-safe cleaner like dawn dish soap.

Frequently Asked Questions

I’m going to add some FAQS here that I get from readers and also to help with visibility online so people can find this post. If you have any questions, I encourage you to leave a comment below. I will add to this FAQ over time.

Can Fish Survive Marine Velvet?

Yes, fish can survive Marine Velvet disease. They will need treatment to survive, however. Surviving fish have been known to develop an immunity to the disease, but can still be carriers. This is why we must treat the disease and completely eradicate it from your display tank.

How Do You Get Rid Of Marine Velvet?

There are two medications that are effective in getting rid of Marine Velvet disease. The most available is chelated copper using a product like Copper Power. The other medication is chloroquine phosphate, which is more effective but difficult to obtain. Both need to be treated in a hospital tank, and a fallow period must be done in the display tank to remove it completely.

How Do You Treat Velvet?

You need to treat Velvet with either chelated copper or chloroquine phosphate in a hospital tank, then have a 76-day fallow period in your display tank to completely remove it from the system.

How Long Can Marine Velvet Live Without A Host?

Marine Velvet can live without a host fish for up to 72 days per a Texas A&M study. This is why I recommend a 76-day fallow period. This builds a buffer so you can ensure complete eradication

How Long Can A Fish Live With Velvet?

It depends on the fish, but generally most fish cannot live with Velvet longer than 1-2 days. Some will die before they have any visible symptoms! This is why it’s critical for you to begin treatment as soon as possible. It is not a disease to take lightly!

The most resistant fish in our hobby are those with a thick slime coat. These would be fish like clownfish, mandarins, wrasses, and rabbitfish. Nevertheless, Velvet is capable of wiping out every fish in your aquarium!

References

Conclusion

I hope this guide got you all the information you need to combat this tank killer. Marine Velvet disease shouldn’t be taken lightly. You should run to your local fish store to get supplies now if you are dealing with it. If you are not dealing with it, work on building up your medicine cabinet now. It may save your fish’s life one day or save a fellow reefer’s fish. If you have any questions, please leave a comment below. I’ve successfully fought off Velvet in the past and I am happy to share my experience with you.

by Mark

Mark is the founder of Aquarium Store Depot. He started in the aquarium hobby at the age of 11 and along the way worked at local fish stores. He has kept freshwater tanks, ponds, and reef tanks for over 25 years. His site was created to share his knowledge and unique teaching style on a larger scale. He has worked on making aquarium and pond keeping approachable. Mark has been featured in two books about aquarium keeping - both best sellers on Amazon. Each year, he continues to help his readers and clients with knowledge, professional builds, and troubleshooting.

25 COMMENTS

  1. We have a 90 gallon tank. Have lost two 3 clown fish, one mandarin goby, one cardinal and an anthias. We think the anthias is who possibly spread it. Our fish all lived several weeks if not longer with the disease. Is that normal for Velvet? I see in one of your posts that fish general die within a few days. Using Polyplab medic currently for about 16 days but doesn’t seem to be working. I have a fire fish left, a clown, yashi goby and a few cardinals. We definitely dont think it is ich…any other ideas/suggestions?

    Reply
    • Hi Lisa. That can happen. Your fish may have developed a resistance to the disease. You will still have issues with any new additions. It would be best to try to eliminate the disease bye having the tank go fishless for 76 days. Do you have any pictures to share when the outbreak fast occurred? You might have been brook

      Reply
  2. I emptied 90% of the water in my 125 display and removed all the rock all my fish are in copper safe for min 30 days do i leave my tank empty for 30 days or it has to be 76 days?

    Reply
    • Your display tank would need to remain fishless for 76 days while you treat the fish in a separate tank. If you put copper in your display, you will not be able to house inverts anymore as copper will leach into the system and kil them over time. Once a tank is medicated with copper, it effectively becomes a fish only tank.

      Reply
      • One more question wbile my fish are in copper my 125 gal has some water in it and the sump as well it says velvet can lice off of light my tank is next to a window will the velvet survive on just light? If i go 72 days fishless but the velvets using light wont it reinfect my fish

      • Yes, velvet can live on light. As long as the tank goes fishless for 76 days you should be fine. Without a host – they cannot continue to reproduce and the lifecycle is broken

  3. I have had velvet in my tank now everything is out except a sting ray everyone says that it can’t get ich or velvet. So now waiting the 76 days to be safe and the sting ray is the only thing in the tank

    Reply
    • Hi Anthony,

      I’ve heard it about ich but not with velvet. Likely because velvet isn’t as common with large predator tanks. I can’t really say for sure. I mostly know that Sting Rays cannot be treated with copper. They would have to be treated with Chloroquine Phosphate.

      Reply
  4. Is there a possible way to treat this in a display tank? I work at a pet store and we don’t have enough hospital tanks or enough tanks in general for the amount of fish we have to treat.

    we don’t have cp or copper to treat but we do have chemipure elite and phosguard. I’m wondering if I can treat with this and if i can save these fish with what we have in the display tanks…
    i understand the chances of survival are low and fast reaction time is crucial .

    Reply
    • Hi Kat,

      It is possible to treat it in a display tank if you are okay with never keeping corals in there. You would have to remove the rocks and the substrate to avoid any leech. Unfortunately, the problem you may run into with taking out rocks and substrate is losing a lot of the beneficial bacteria. You will want to monitor your Ammonia and Nitrite levels if you attempt this.

      You cannot treat Marine Velvet with Chemipure or Phosguard. CP, Copper, and Formalin are the only effective treatments. Formalin only works as temporary relief though – and is increasingly becoming illegal in multiple states.

      Reply
  5. Hi mark, I am new to this hobby. Thanks for your sharing. I will try your advices treatment asap. I got my Majestic angelfish in 11 jan. The disease breakout on early march. Can you share more advice whether we should have fresh water bath for every new fish ?

    Reply
    • Hi Louis,

      If this is Velvet, you will want to treat every fish in the tank. Ideally, in a hospital tank. The medications you will need to use against Velvet are strong and will render an aquarium unsuitable for corals and inverts in the future if used in the display tank. If you treat in a hospital tank, you will need to watch out for ammonia levels since the tank(s) will likely be overstocked to house a fish. When I’ve had to do a full tank treatment like this, I was usually changing water every 3 days or so to keep levels down (it sucks, which is why I just quarantine everything now). Not to mention you will need to leave your display tank fishless for 6 weeks to eliminate the velvet in the tank.

      For expensive fish like a Majestic fish, I would highly recommend only purchasing quarantined fish from an established seller like TSM Corals. If you operate on that budget, I would just step up to a better vendor to ensure you get the highest quality and healthiest fish you can purchase. Many local stores will not quarantine and get larger specimens from the wild — which typically will go through a lot of stress and make them prone to many illnesses.

      It may seem expensive to spend over $200 for a quarantined Majestic, but the amount of loses you can potentially take from fish like that will outweigh it. Otherwise as a beginner, it’s best to stick to smaller and hardier fish that are less expensive and resistant to stress and disease.

      Reply
  6. I just lost all 12 fish in my 90 gallon tank to velvet, I suspect. I only have a fire fish goby and banded coral shrimp left. I did add one treatment of copper. The goby seems unaffected. What should I do from here? My tank is 2 months old. All parameters were good. I can’t catch the goby and don’t have a qt.

    Reply
    • Hi Glenn,

      The best advice I could give you would be to get the goby out of the tank in order to let it go fishless. A fish can develop a resistance to marine velvet disease after being exposed, but will continue to be a carrier. You will continue to have losses in the display tank until the disease is completely removed from the tank. You may need to remove the rock the goby is hiding in and place it in a bucket or rubbermaid. Remove the fish at a later time when it is not in the rock. Once you have it out, give the proper medications to the fish so the life cycle can be broken. Let your display go fishless for 6 weeks. You can also purchase corals then start the clock after the last coral is added. Best of luck to you.

      Reply
  7. Hi Mark,
    Thank you for writing this article, it’s very helpful, I’m going through what i think is a marine velvet outbreak, all my fish is now in a quarantine tank, I was only able to get Cupramine from my local fish shop, the recommended dosage is 20 drops per 40ltrs of salt water, ive done 20 drops over 2 days, 10 per day,then another 20 drops repeating the process, done the seachem test with a 0.5mg/l, is this the therapeutic level?
    What is the best method of returning the fish back to the DT after 76 days without contaminating the DT, I would have to use the net to catch them again, at what stage do I start doing water changes to bring the copper levels to zero in the quarantine tank, best recommended method please.

    Reply
    • Hi Stan,

      The way I’ve done it is to make a water change then net the fish an place into your display tank water. You should have the parameters the same with salinity, temp, and pH. I use a speciman container for the transfer. I’ve never had an issue doing it this way. There are traces of copper in our reef systems, it’s just usually minimal. You can also place carbon in your sump or filter as added protection.

      Reply
  8. Hi Mark, A great article thank you. I am going through a velvet attack now and i already lost a few of my favourite fishes… and i hope to save what is left. So at this point i am moving the rest of the fish to QT to start the treatment. Have a few question:
    1. I only could you find seachem copper and ruby reef rally.. do you think i can manage with it.
    2. I have many corals and CUCs in my DT. Won’t the velvet survive on other organisms like corals and CUC?

    Thanks.

    Reply
    • Hi Shanmuga,

      Both seachem copper and ruby reef can work. Ruby Reef is good for short term relief. Seachem copper is ionic copperr, which may be incompatible with some fish.

      If you have any corals or CUC, the medication will kill it. It’s best to use copper in a separate quarantine tank.

      Reply
  9. Hi thanks for the explanation! I am new to the hobby and currently have 2 new clowns, they are the first fish in my new tank. It appears the male clown has velvet or ich, I don’t really think it was in my tank to start since they were the first fish, the female is fine but the male has been struggling since last night, swimming in the return power head, I’m just curious as to how my new fish developed this? Will the other one get it? And since I just bought this tank, rock, sand etc, I’m assuming I’m basically just starting over?

    Reply
    • Hi Mike,

      Velvet and Ich are highly contagious. It can be spread to any fish in the tank. I would put both of them in a hospital tank and start treatment. Check out the pictures I supplied to see if you can determine if it is ich or velvet. It could be brooke too. Time is really the thing you work again when fighting diseases

      Reply
  10. Thanks for reinforcing the basics.
    I find humblefish a fantastic source after continually losing fish for 3 months…I now QT EVERYTHING.

    Any comment, or experience with Seachem Metroplex?

    Reply
    • Hi Nigel,

      Yes, I know Bobby well (Humblefish). He’s guided me so much in the ways of quarantine and I’m extremely happy that he branched out on his own to make his own forum. He has no skin in the game – he’s all about helping hobbyists.

      Regarding Seachem Metroplex, I’m a huge fan of it when combined with Seachem focus for it to be used against internal parasites. I’m not aware of it being effective against Marine Velvet. I’ve heard that Metroplex is effective against treating the internal side of Brook and Uronema. For Velvet, I have used Copper Power and CP with great results.

      Reply
  11. This is great article and very helpful.
    I lost 2 clown fish and firefish 3 weeks ago due to velvet .now my Qt tank is cycled and I have copper power and hanna checker ready incase new clowns and firefish will get it in Qt tank.
    My issue is my yellow watchman Goby is still in Dt tank and seem never been affected by it at all and impossible to catch in rock work too. Lol
    Other than that nothing was put in Dt tank for 22 days no corals or inverts or fish .I tend to go 80 days like that but not sure how that single super healthy and fast goby can affect the process after I Qt 3 new fish.

    Reply
    • Thanks for your comment Pavel,

      Sorry for your loss. It’s a helpless feeling to lose fish over this disease. The good thing is you have the supplies and are prepared now.

      Most hobbyist with experience in dealing with Velvet would recommend that you get your Goby out and go fallow. I’m part of this camp. Would it be difficult for you to take apart your aquascape to get him out? He will always be a carrier of the disease and has developed some immunity to it, but any new fish you introduce may get sick and die. A second outbreak can cause additional headache and death to your goby.

      My recommendation would be to get your Goby out. If it’s a smaller tank, you can always just have him in there and just load up on corals and inverts.

      Reply

Leave a Comment

ALSO IN THE AQUARIUMSTOREDEPOT.COM BLOG

How To Treat Ich On Fish - 6 Prevention Tips and 1 Go To Cure!
Have you noticed white spots all over your aquarium fish? This is a symptom of ich, and you're going to need to treat it soon. The good news is that you can solve this problem with the right knowledge and medications, and that's just what this article is about!
10 Types Of Aquarium Algae (And How To Get Rid Of Them!)
Do you have algae in your fish tank? This is a problem that all aquarists deal with from time to time. In fact, algae are present in all aquariums to some extent. It can get a little out of control sometimes, but fortunately, there are ways to get your tank cleaned up and looking great again.
Rummy Nose Tetra - Everything you wanted to know
The Rummy nose tetra is a beautiful freshwater fish that is easy to keep, breed, and care for. The common name for Rummy nose tetra in the aquarium world is brilliant rummy nose tetra, red nose tetra, and Firehead tetra. It has bright red heads with horizontal stripes of black and white tail, resembling the fire flames. In this article, we are going to cover everything about Rummy nose tetra.