How to Get Rid of Dinoflagellates - Control, Prevention, & Removal

September 26, 2018 1 Comment

How to Get Rid of Dinoflagellates - Control, Prevention, & Removal

What Are Dinoflagellates?

In the Wild

Dinoflagellates are protists, an organism that can function as a plant and an animal at the same time. Some dinoflagellates eat other protozoa; some generate energy through photosynthesis; some can do both. In the wild, there are about 1,700 different kinds of marine dinoflagellates and 200 freshwater kinds. They are important part of the food chain, providing nourishment for other sea creatures. In a natural environment, they're a crucial member of the ecosystem. 

In Your Tank

Unfortunately, dinoflagellates quickly become a nuisance in an aquarium environment. 

Dinoflagellates quickly overrun the surface in your aquarium because there is no specific ecosystem for them to survive. Depending on the conditions, dinoflagellates can multiply up to a million cells in one milliliter of water in just a short period of time. The bigger the population, a higher chance that it will make the water toxic and can kill other life form inside your tank. So, it's important to control dinoflagellate population as early as possible before it occupies every space inside your aquarium. 

What Should I Look For?

It's not like you're going to go to the store and buy some dinos to dump into your tank; these pests are introduced to your tank accidentally. Your tank can get this from food, corals, rocks, and other aquatic plants. Dinos are very resilient because it can live without eating anything for a long time unlike any other life form like algae.

Nutrients are present in your tank which gives energy to fishes and plants. Even though your tank lacks nutrients, dinos can still survive. It is possible for your tank to have dinos if the nitrates and phosphates level in your aquarium is so close to zero. It is important to regularly check your tank before it becomes too late. Better to be sure, because dinos can look a lot like cyanobacteria or other kinds of algae to the untrained eye. 

Identifying What Dinoflagellate You're Dealing With

The best way to approach your dino problem is to first figure out what kind of dino has moved into your aquarium. 

The most common dinoflagellate (or "dino" for short) to see in an aquarium is a slimy, stringy brown variety, commonly known as Brown Slime Algae. Most aquarium enthusiasts have dubbed it "the brown menace." They're not all brown, though. They also come in white, yellow, and various shades of green. 

In more technical terms, there are four main dinoflagellates you'll see in your aquarium: 

  • Gyrodinium aureolum
  • Prorocentrum minimum
  • Heterocapsa triquetra
  • Scrippsiella trochoidea

Some of the things all of these guys have in common is that they: 

  • Are mucous-like (sometimes described as runny boogers)
  • Produce air bubbles
  • Trap air bubbles between the slime and the glass of the tank
  • Spread quickly, covering all surfaces with coral being a particular favorite

Here's an easy test you can do to determine if you have algae or dinos: 

  • Scoop some sludge and water out of your tank.
  • Put the sludgy water in a clear container with a lid.
  • Shake the container to break up all of the floating bits.
  • Filter the water either through paper towel or a filter sock into a second clear container.
  • Leave the second container of filtered water in a sunny location.
  • Monitor the water for changes, namely the reappearance of mucous-like strands.

Eventually, dinoflagellates will regroup after they've been filtered. Algae will remain separated. So, if the strands of go show up, you know you have dinos! 

How Do I Get Dinoflagellates Under Control?

Dinos aren't necessarily a bad thing. When there aren't too many of them, they're part of the ecosystem. But if you provide an ultra low nutrient tank with no biodiversity, they'll make themselves known quickly. The best way to tackle them varies on how bad your case is. 

How to Deal with Dinos:

  • The first step is removal. Others might think that they need to remove all the water and change it with a new one, but that is definitely wrong. Along the process of removing dinos, changing the water in your tank will make things worse. Dinos thrive in nutrient straved tanks and cleaning water will eliminate nutrients and allow Dinos to thrive further. It advisable that you remove the dinos manually with the use of filter sock instead of changing water.
  • Another way to surely get rid of dinos is by increasing the amount of nutrients in your tank. You should increase nitrates and phosphates to observable level. You may consider nitrates with NeoNiitro and NeoPhos from Brightwell Aquatics. Even a freshwater solution like SeaChem Flourish will work as well.
  • You also need to remove nutrient reducing media like GFO. It is common for many tanks to have dino outbreak because of the presence of GFO. When you get rid of GFO’s, it is easier for you to increase the nutrient level in your tank and maintain it in the long run.
  • Along the process of dealing with dinos, having carbon present in your tank will help neutralize the toxins they release as they die off. This will protect your livestock.
  • Adjust the pH of your tank. A pH of +8.4 is a good level for reef tanks to avoid dino blooms. The pH is something you can play with over time to determine what works best for your tank.
  • Control the lighting in your tank because the most common dinos derive their energy from photosynthesis, so killing the lights will also kill them. You can use a blackout curtain or cardboard with duct tape around the tank and on top of the tank. Blackouts should last at least 72 hours.
  • Add small doses of hydrogen peroxide to your tank. The general rule is 1 ml per 10 gallons of water.
  • Use a UV Sterilizer. Get a high quality and well sized UV Sterilizer and run it 24-7. The UV sterilizer will be most effective during the blackout period. This method does not work when dealing with H. triquetra, however. You can use a Jabeo UV as a cheap solution or an Aqua UV for a high-end solution.

Jabeo UV Sterilizer


    How Can I Prevent Dinoflagellates in the First Place?

    Biodiversity is a major reason why new tanks get dinos when they hit low nutrient conditions. A biodiverse tank has multiple organisms that compete with dinos and keep them from thriving. When choosing the type of rock you are going to use, keep biodiversity in mind. You can choose between live rock and complete dry rock or a hybrid, but I would caution against going with a 100% dry rock and dry sand start.

    Dry rock is devoid of biodiversity while in a live rock tank you don’t usually see dinos. It is hard for them to multiply because there too many competitors even in a low nutrient environment.

    The problem will be the availability of the live rock because it is quite hard to find nowadays and is expensive to boot. 

    These days - Real Reef Live Rock is the best source for aquacultured live rock that has the right balance of biodiversity while still being free of pests. This is the best option for those who who not use a sand bed and going bare bottom.

    Real Reef Rock

    For those people who are not able to procure live rock or have a sand bed, the other option would be to introduce microfauna and bacteria through an aquaculture facility like Indo Pacific Sea Farms. They have been around for many years and their live sand activator and wondermud are just the ticket for increasing biodiversity.

    Remove Overabundant Food Sources (AKA Your Inverts if an outbreak occurs)

    Snails encourage dinoflagellates to settle in and make your tank their home. Well, they don't actually do it when they're alive: a dead snail is a feast for a population of dinoflagellate. Dinos will wreck havoc on an invert population. Anything that attempts to eat it can be poisoned to death and the toxins they release will kill most inverts including microfauna. Make sure you're removing any dead snails, fish, and corals from the tank. Because it's hard to tell if your snails are alive, the most foolproof way to prevent that is by removing of the snails altogether. Once your dino problem is under control, they can be returned to the tank. 

    Balance Tank Nutrients

    A couple of specific nutrient-related things you can monitor and manage in your tank are:

    • Magnesium: levels should be somewhere in the 1400-1600ppm range
    • pH levels (as mentioned above)
    • Bacteria: introducing new bacteria to your tank will deprive dinos of nutrients. Live Rock and Live Sand are your best friends to maintain biodiversity!!!
    • Nitrates - Work on getting these above 0 and maintaining it. A little bit of nitrates is good for your tank
    • Phosphates - Don't let your phosphates hit 0 

    Don't Create an Undernourished Environment

    A tank that is starved for nutrition can cause a dino population to pop up too. Usually this situation comes about when you make some major change to the landscape or population of your tank, and the food shortage is abrupt. Dinos don't actually need that much physical food to eat, especially since most are also photosynthetic. So, if other bacteria or phytoplankton in your tank die out from lack of nutrients, it removes the dinoflagellate's primary competition and gives them room to thrive.

    Have Proper Equipment

    Quality equipment is important for the overall health of your tank, whether it's a 10 gallon aquarium or a 100-gallon aquarium. While there are several factors that help dinoflagellates take over, a poor equipment planning controlling parameters tops the list.

    When dying, dinoflagellates release toxins into your water. So, it's essential to purify the water consistently, both during and after your dinoflagellate infestation.

    Here are a few suggestions to help setup and maintain a proper tank: 

    • Add granular activated carbon to your filtration system.
    • Get a skimmer and set it run often enough that it needs to be emptied a couple times a day. Remember to replace however much you use with the same amount of water.
    • Use an algae scrubber. An Algae scrubber will maintain a healthy population of algae that will keep dinos at bay. Make sure you adjust the lighting schedule if your nutrients start to bottom out! 
    • Regularly test your water's nutrients - nitrates & phosphate and understand the nutrient consumption on your tank. Modern reefs these days can strip nutrients completely clean and may require dosing of nitrates and phosphates to stay at a healthy level. Knowing your consumption puts you in control of your reef tank!  
    However you choose to combat your dinoflagellates, know you're not alone. Just about every modern aquarium enthusiast has done battle with the brown menace. There is hope: you just need to be consistent and patient in your approach killing them off.

    1 Response

    Anthony Burgholzer
    Anthony Burgholzer

    November 11, 2018

    I would like to comment on this article about dino’s. I had them for about a year or so in my reefer 250 and in my 29 biocube. I tried EVERYTHING you have listed here in this article. All of these suggested removal approaches only seemed to knock them back a bit. None of them and I repeat NONE of them worked to get rid of the dino’s. They are the most stubborn and hardy creatures I have ever dealt with to the point of almost giving up!

    I finally started to make headway by keeping my PH up to at least 8.4 to 8.6. Additionally I thought I would try a new approach by using only DI water(I’m sure RO would work the same). It is a known fact that saltwater organisms do not live in pure water and many reefers use this method as a water bath or dip to get rid of unwanted critters on their new coral, live rock or whatever. I used this approach by using an airline as a siphon tube and a small bucket of DI water held at least to head high(sometimes I just placed the bucket on my head cause I got tired LOL!). Slowly siphoning the water directly on the sand bed where they mostly seem to hang out. I did this everyday for a couple of weeks and then every other day for another couple of weeks and now I’m down to twice a week with no dino’s in sight, however, I am still doing this and will be for a while (another month) just to be sure they are GONE! I really hope that someone can use what I have suggested here and get the same or better results. Happy Reefing, AB.

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