Reef By Steele
10K Club member
I have recently had customers reaching out with dinoflagellates issues seeking solutions. I have never personally fought dinoflagellates (however I might have a pretty severe case in my frag system which has been greatly ignored since we started this business). More on that later. I have however read quite a bit about them as I study the items we culture. The number one thing that I have seen recurring in thread after thread and website after website is that they are a scourge upon the ocean. Ok maybe that is a bit exaggerated but I have read of fellow aquarists quiting or threatening to quit the hobby over dinos.
Here is what I know about them, and information I gathered from numerous threads here and in other forums.
- For starters everybody most likely has dinoflagellates in their aquarium.
- They generally become a nuisance from either a significant drop in nitrates and phosphate, sterilization, or other significant event that wipes out other competing life forms allowing dinos to flourish.
- There is no silver bullet, magical fix or quick solution.
- There are steps that can be taken to avoid dinoflagellates and or a resurgence once they have been beaten back.
- There are different strains of dinoflagellates just as there are thousands of strains of phytoplankton in the ocean. And identification is one of the first steps in combating them
- Patience and diligence can and will restore an aquarium back to its condition prior to the outbreak or even better.
Here is an attempt to simplify the information into a concise location. With links to many of the threads I read to gather this information. As stated above, I have not personally used these protocols, but also as hinted I will be if I identify dinos as the issue in my neglected frag system. Nothing here is 100% effective nor quick, but if you commit to following through, the odds are pretty good that you will reduce harm and return your tank to a more stable environment.
There are many great contributors to the hobby on www.reef2reef.com and most of this information has been gathered through hours of reading their experiences and trying to pull the information into this post or links to supporting information. Here is one such thread with posts in this "Are you Tired" thread
There are 5 different dinoflagellates we commonly find in our aquariums. As stated before, if your system has any age to it, some mix of these are probably present. Like bacteria, you can't really avoid some blend of them entirely, nor should you try. They are a very natural microorganism that typically leads a very marginal existence alongside other, more dominant competitors. These competitors include diatoms, bacterial film, film algae, coralline algae, sponges, GHA, turf, corals, pods, etc. Some of these competitors are seen as desirable while others are not, but they all take up surface space when a tank is healthy and stable. Maintaining a healthy population of these competitors makes it more difficult for dinos to overtake the surface areas. Dinoflagellates are not some super monsters poised to overtake every tank they encounter, rather they are marginal scavengers that only thrive once a reef has starved, sterilized, poisoned, or otherwise weakened some of the natural (desired or otherwise) surface competitors.
Here is the break down for what I found:
- Do I have dinoflagellates?
- Identify the type of dinoflagellate I have.
- Universal treatment protocols.
- Specific treatment protocol for Ostreopsis, Prorocentrum, Small Cell Amphidinium & Coolia (motile strains)
- Specific treatment protocol for Large Cell Amphidinium
- Follow up post treatment and protocols to lessen recurrence.
1. Do I have dinoflagellates?
Each of the 5 common species has a slightly different look in the tank. Sometimes they look very different and meld into any of the other competitors mentioned above. Sometimes they are confused with diatoms, cyanobacteria, bacterial film and chrysophytes to name a common few. They all form some kind of mucus. Some have long strands with bubbles while others do not. The mucus could be reddish, brown, gold, or in between. They can take over rock, sand, glass, plastics, even a refugium. You don't need a microscope to find out if the gunk is dinoflagellates but will be best to use one to identify which type you have if this test I found comes back positive.
The coffee filter test:
- Syphon out a good sample of the gunk along with some tank water.
- Place in a container with a lid and shake very hard for 30 seconds or so. The gunk should be dissolved now.
- Pour the solution through a coffee filter into a clear glass. The water should be largely clear now.
- Place the jar under a light source for roughly an hour.
- If the gunk coagulates back into a glob, well, welcome to the club nobody really wants to be in.
2. Identify the type of dinoflagellate.
We can make some educated guesses without a microscope based on appearance and location, but I strongly encourage everyone to confirm which species is/are present. It is very common to have more than one species. Some are toxic while others are just a visual nuisance. Most respond well to UV treatment while one does not. They have different competitors too.
You can buy a student microscope for under $50 that will work just fine. 400X magnification is all you need. I started out using a child’s microscope borrowed from my daughter before we started our business. You will use your camera phone to take a video through the eyepiece. Experiment with zooming in with the camera for a bit more magnification. You might consider buying a phone cradle especially if your hands are as rock solid as mine (lol). Making a video helps as the swim pattern helps to determine the species almost as much as the shape especially when using lesser grade microscopes and shaky camera hands. No special protocol about slide prep, just use a pipette to suck up gunk & water and drop it on the slide. You get 400X by using the 10X eyepiece and 40X barrel. Now you are ready to identify them. I found this source from @taricha to be an excellent resource.
Dinoflagellate Identification guide
It is important to get a proper ID on your dino(s) as it determines a few important things:
- Do I need to (properly) implement UV equipment?
- Do I need to do a blackout of the tank
- Do I need to be concerned with potentially serious toxins?
- Should I order and dose some silicates?
3. Universal treatment protocols.
- Ensure that the tank always has measurable residual amounts of nitrate and phosphate. Any nitrate test kit will do, but you need Hanna ULR for phosphate. Target roughly 10/.1. If you are 0 on phosphates, be prepared to dose heavily to get them to a noticeable. It binds to your rock and sand, one of the reasons we found it hard to get PO4 down in our XXL750 Predator tank. Stock up on Hanna reagents!
- It is important to FIRST dose up PO4 to a stable level. Adding nitrate to a depleted tank will hammer your PO4 and stress/kill a lot of coral.
- Dose a nitrate and/or phosphate solution as necessary we recommend Brightwell NeoNitro and NeoPhos. Test almost daily -- at least initially -- if you are deficient.
- If your dinos are presently based in the sand, it is recommended that you dose silicates to restore competitive diatom populations. Brightwell SpongeExcel is the most common source used. Detailed dosing instructions here.
- Avoid water changes unless it is an emergency. Dinos do seem to deplete certain traces. You will get a mini bloom with a water change. Also, it removes nutrients.
- Consider dosing live bacteria such as Microbacter7 which can help by increasing the heterotrophic bacteria in your system to compete for surface area again monitor nitrates and phosphates.
- Stop any amino acid dosing. Same goes for particulate coral foods. The dino mucus webs just grab it all anyway as their food source. It is also fine to feed the fish more. Fish waste is an ideal food source for competing microorganisms. Your tank needs more of those. However do not rely solely on increased feedings to restore NO3 and PO4. Dose!
- Basting off dinos is fine, but avoid "deep cleanings". We do these things to remove films and algae, but we need that population to recover. This is a common cause of relapse.
- If you are dosing 2-part or CaRx, watch your alkalinity. I have read consumption collapsed during (ostreopsis) outbreaks but rebounded shortly after.
- Higher pH is better than lower pH. I don't know why, but the pattern was unmistakable. I know it helps rebuild coralline. Open some windows when you can.
- If you have a UV lamp, it is a good idea to deploy it as described in Section 4 even if you don't (right now) see the presence of free swimming dinos. The dino species dominating your tank can shift over the course of days. Plus the UV performs other functions that are helpful in times of biome stress.
- Introduce live rock and/or live rubble. Can be ocean sourced or from another established system. If your tank was a dead rock start (and isn't a few years old already), your biome is missing bacteria by count or by genus or both as demonstrated here. While we do not understand how these deficits contribute to dinoflagellate outbreaks, the outbreaks appear primarily with dead rock starts. Some potential live substrate choices are detailed in Section 5.
4. Specific treatment protocol for Ostreopsis, Prorocentrum, Small Cell Amphidinium & Coolia (motile strains).
Tool #1: A properly sized, placed and paced UV install FOR FIGHTING DINOS looks like this:
- Ignore manufacturers recommended specs for sizing and flow! Their numbers are designed to sterilise/kill soft little parasites, bacteria and water borne algae. Those numbers are not designed to eliminate hard shelled protists sporting body armor.
- 1 watt per 3 gallons of tank volume
- Flow should turn over the tank 1-3 times per hour. The bigger the unit relative to tank size, the faster you can go and vice versa. As long as the bulb stays cool enough, you are not running too slow IMO.
- This should be plumbed directly from the display tank and returning back into the display. You can use some PVC to make it quick and easy to install so you can plug it in and go.
- Ensure that the darn thing is running properly. The ballast is good and the bulb is less than 12 months old and hasn't been overheated.
- Baste as frequently as you can so that the dinos pass through the UV.
- To varying degrees, these species go swimming at night. Ostreopsis are the most adventurous of the four and a blackout may not be needed to get them under control. The other three may require a blackout to get them moving into the water column. Try a two day blackout first to see if that is enough. Wrap the tank in cardboard or black trash bags. Turn off the fuge light if you have one going.
- Blacking out the tank without a proper UV in place is very unlikely to help. Yes, dinos are photosynthetic, but so is the needed competition. When the lights come back up you are back where you started.
Tool #2: The Poor Man/Woman's UV
If a UV isn't in the budget, or is stuck on a boat in Long Beach, or you just want to go after these guys a little harder, you can affix sheets of filter floss to the sides of the tank like this. Ostreopsis really prefer this surface when placed in a high flow/light area. Wherever your dinos seem to be hanging about is the right place to affix the floss. I used suction cups, zip ties to fasten the floss. Repeated basting of infested surfaces is encouraged. Rinse the floss each evening (before the lights go down) in fresh water and replace.
Tool #3: Removing toxins
All four of these have some level of toxin, with Ostreopsis and Proro having pretty high levels. It is a good idea to run carbon and refresh it more frequently than usual. PSA: IF ANYONE IN THE HOUSEHOLD HAS RESPIRATORY ISSUES LIKE ASTHMA, take some added caution. You want to shut off the skimmer to avoid aerosolizing and improve ventilation. There have been reports of respiratory distress in the presence of ostreopsis. Because I had bad experience with palytoxin I recommend exercising caution at all times as we may not understand all the risks from everything in our aquariums.
Tool #4 Filtering
Our common dinos are rather small measuring 5-40 microns. The mucus can be trapped and contain many/most of the dinos as long as they choose to remain in the mucus. But as you will see on the microscope slide, they roam fairly freely from the mucus. Perhaps a 5 micron sock could be deployed to trap dinos once syphoned out. I don't have much conviction on efficacy, but if you have the energy it cannot hurt. Or possibly use filter floss in your filter socks and rinse daily as above.
Section 5: Treatment protocol for Large Cell Amphidinium
If you are reading this section I have good news and bad news. Bad news: these are the most difficult species to remove. They cling to the sand and do not swim around at night like the others will, eventually passing through the UV to be damaged or destroyed. The good news is that they are really quite harmless. They have very little toxicity; they just look a little worse than a good diatom population. Most steps people deploy to eradicate them (out of some desperation) are much more destabilizing than the LC amphids will ever be. If you really need that white sand back, be prepared to be patient. Here is a thread of some dino horror stories.
Tool #1: Dosing silicates to restore diatom population
This is very harmless and is really the primary tool. The goal here is to feed a variety of diatoms in particular along with other sand dwelling microorganisms to the point where they outcompete the amphids. Brightwell SpongeExcel is the off the shelf solution for this. The target range of SiO2 is .5 to 1 ppm in the tank and holding it there long enough for the diatoms to repopulate. Make sure you are not running any GFO as it will bind up the silicate. Unfortunately, there don't seem to be many good testing options for silicates other than a $50 Hanna low range silica hi705. Continue to pull microscope samples from the sand bed to see if diatoms are increasing. Diatoms look like this. If you prefer precise dosing instructions, there is this detailed post also courtesy of.
Tool #2: Adding in some microbial diversity via live rock, mud, sand or rubble from the ocean or another established captive reef
This is not a quick fix but is very helpful in recreating a more competitive, balanced and robust biome.
Tool #3: Adding in some sand based CUC and improving the pod population our Dino Destroyer Buffet has a unique blend of three copepods known to eat amphid dinoflagellates. This is generally safe so long as there aren't other more toxic dino species mixed in. While not a total solution, several people reported good results weighting down some chaeto on the sand bed. Chaeto houses pods, and is also believed to have some alleopathic properties against dinos.
Tool #4: Manual removal of Amphids, or the sandbed all together
I struggle with mentioning this one, but it always comes up as a question. Results are mixed and often temporary and I just don't believe they are worth the risks and disruption when the biome is already a bit noisy. But if you're becoming desperate, let's at least run through some considerations.
- Syphoning off the top layer and RODI rinsing it may be okay. You will kill some dinos that way, but their competition will also be killed.
- Removing, rinsing and replacing a complete section every now and then may be okay, but the same trade off exists.
- MOVING the entire sand bed to the (dark) sump has been done. It does help maintain your biological filtration which is good. Results are still out on that though.
- An old, relatively deep and previously unmanaged sandbed can contain some pockets of hydrogen sulfide which is toxic if released into the tank. Extremely rare.
- I will just point out that several reefers chose to leave the sandbed completely undisturbed and reported good results in conjunction with silicate dosing.
As stated at the outset, LC Amphid cling tight to the sand bed and do not migrate into the water at night where we can zap them in the UV. That said, there are other potential benefits to running a UV. They include:
- LC Amphids are the species most commonly found IN COMBINATION with other swimming species that will make it into the UV.
- UV oxidizes some trace elements that dinos need; e.g. Iron (Fe)
- UV also breaks down certain complex organic molecules that dinos crave along with dino related toxins
Section 6: Avoiding relapse & What to expect next
Avoiding relapse is really pretty simple once the dinos begin to fade. Just keep doing what you've been doing, steadily. It can take some time for the competitive microorganisms, algae and bacteria to fully spool up and it doesn't always look attractive. Relish in it. It is a partial ugly phase you just have to get through.
- Avoid dosing amino acids for a long time. It is a dinoflagellate superfood.
- Maintain nutrient levels. This can be hard to do when you begin to see the old "villains" return. Diatoms and cyanobacteria outbreaks are nearly a given.
- Large Cell Amphidinium tanks SHOULD be seeing strong growth of diatoms on the sand. The color should be transitioning from a reddish color to a more rusty tan color. The glass should be getting a brown film.
- Syphon out the cyano and stay the course on nutrients. You don't have to maintain 10/.1 nitrate to phosphate anymore but residual nutrients must always be present.
- I find cyanobacteria blooms are transitional in our systems; they often appear when nutrient trends are shifting rich=>poor and vice versa. Keep nutrients steady & balanced and the cyano will be displaced. Eventually. Chemiclean is a bad quick fix IMO.
- Keep testing for residual nutrients every couple of days until it gets boringly stable and predictable. Then test weekly.
- Next will come some green film and perhaps some GHA. If you let one or both nutrients bottom out now, that is just fodder for the dinos to return. It is just another ugly phase, not the end of the world.
- Now that you have some green stuff it is time to add some herbivores and CUC. Don't skimp here. Get working fish to work. Fish waste is the ideal food source for a healthy biome. Dosing nitrate and phosphate was a stopgap.
- Keep feeding the fish; upgrade your export if you have to (skim, refugium) but try to avoid GFO and NO CHEMICLEAN OR EQUIVALENT AT ALL.
- If the GHA builds up, try to stick with manual removal. Squirt it with a little H2O2 a couple times to soften it up and then pinch or scrub it off. Herbivores strongly prefer new growth and won't go after "old growth" GHA.
- If you are a Vibrant fan, hold off as long as you can and go super slow with it. Remember, it (allegedly) contains bacteria and a carbon source which will lower your nutrient levels. It also contains an algaecide (not fluconazole) very similar to that in AlgaeFix. See here.
The range of time it takes to fully resolve a dinoflagellate outbreak varies greatly. I have seen virtually overnight success following a blackout with a well implemented UV on ostreopsis and prorocentrum. On the flipside, I've seen LC and SC Amphidinium take many many months.
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