Introduction

This guide is for the reef aquarium hobbyist who has a suspected dinoflagellate bloom that has not been controlled by normal algae reduction methods.

It is written with the goal of helping the hobbyist to understand what conditions allowed the bloom to occur, what kind of dinoflagellates are present, how the bloom has affected the system, and how to pursue the most successful treatments to reverse the effects and end the bloom.

Overview

• A new tank, a system flooded with carbon-fed bacteria, or a very low nutrient system with weak or declining biodiversity provides a receptive habitat for an organism with the right traits. See Tank Conditions
• The dinoflagellates that we fight have a set of traits that answer the challenges these systems pose: mobility, mucus & strands, toxins, nutrient strategies (acquisition, storage, and depletion), armor and cysts. See Traits
• Dinos use their traits to colonize the habitat, multiply under the conditions available, and then shape the habitat to monopolize available resources.
• Toxins, mucus mats, organics scavenging, nutrient depletion, rapid reproduction, and high cell density combine to allow dinos to force out or kill what little diversity there was, and create space for things that serve the dinos purpose - mostly associated bacteria.
• The more advanced the bloom - in cell numbers, toxin content, mucus coverage, and nutrients locked up in dinos/mucus/bacterial associates - the harder it is to remediate the system, and the more comprehensive the remediation needs to be. See Types of Dinos for individual species effects
• An immature dino bloom that still has diverse competitors might be remediated by simply elevating nutrients, but adding nutrients to a mature bloom often merely intensifies the bloom.
• In a mature bloom, all the measures of the bloom progress must be remediated: toxin content, cell numbers, nutrient lock-up, mucus coverage, and biodiversity may even need to be (re)introduced from another system. See Treatment
• Once remediation is completed, with biodiversity reestablished - the dinos are prevented from re-bloom by these mechanisms: competition for nutrients other than N & P where dinos are not as adept, grazers of many sizes and classes, diversity of bacteria that are not dino associates, surfaces not as friendly to colonization as bare substrate, chemical pressures against dinos such as those known from macroalgae and diatoms. See Prevention
• Keeping nutrients available will allow common algaes to grow (a good thing), which can be controlled in a display by introducing diverse grazers that can reproduce and scale their population to match the algae production, and controlled outside the display by Algae Scrubbers or similar. See Appendix D: Algae Control
• If the tank is starved of nutrients, then the invisible diversity will slowly die out and the system will again become a receptive habitat for a Dino bloom (harsh chemical treatments can fast-track to the same end result). See Appendix B: Zero Nutrients

What are Dinoflagellates?

Dinoflagellates are their own grouping of eukaryotes.

They are named after their whirling pair of flagella, nearly invisible even through a microscope.

They are single celled microbes that are one of the most successful classes of plankton in the ocean.

There are over 2000 species of dinos with wildly varying traits, and a huge genome packed full of DNA stolen from bacteria and algae allowing for their staggering diversity.

Many are autotrophic (photosynthetic) and are often called phytoplankton and algae.  This includes the genus Symbiodinium - the coral symbiont we know as zooxanthellae.

A few dinoflagellates like Amyloodinium (velvet) are parasitic.

Others are heterotrophic or phagotrophic (predators) and consume other microbes or particles.

Proving their diversity, there are even dinoflagellates which are mixotrophic and can vary their feeding habits from autotrophic to heterotrophic according to momentary need. This is the main grouping we seem to be affected by.

What Tank Conditions Allow Dinoflagellates to Bloom? 

The most common account among dino sufferers is that methods for algae control were used and possibly pushed too far.  As algae is reduced, telltale signs of a dinoflagellate bloom appear – bubbly brown patches or brown strings.

Here are a few of the common tank conditions that allow a dino bloom to take place.  

• New “Clean” Tank - Setting up a tank where zero-nitrate and/or zero-phosphate conditions are enforced on the tank from the time it is started seems to predispose a system to an algae bloom of some “ultra-low-nutrient-competitor” such as dinoflagellates. Dinos generally prefer to  colonize rough, uninhabited surfaces over those with established organisms. Healthy coral mucus seems to be the least preferred surface for dinos to colonize. The relationship to green algae is complicated: several strains of toxic dinos seek it out, while a few non-toxic strains do not colonize it successfully.
• Heavy Carbon Dosing - High-carbon environments are generally known to slant the phytoplankton balance toward bacteria and harmful algae bloom (HAB) forming algae. The toxins produced by dinos are majority carbon (~60%) by mass. Heavy carbon dosing feeds a large bacterial population which for many hobbyists is ineffective at outcompeting dinos, likely because dinos possess a strong chemical toolkit that may allow them to shape and co-opt the bacterial population.
• Low Nutrient System - Phosphate (P) and Nitrate (N) starvation can both trigger behavioral changes in some algae (like dinoflagellates) including a switch from autotrophy to heterotrophy and toward the generation of toxins. Low nutrients also reduces the presence and diversity of competitor organisms within a system without significantly harming the dinoflagellates, because they are well adapted to low N & P conditions.
• Strong Chemical Treatments - Tanks that have undergone chemical treatments to eliminate pests may have lost stabilizing biodiversity and could therefore have a habitat that is susceptible to a dino bloom.  

How Do Dinoflagellates Succeed In Our Systems?

Nutrient Strategies

Photosynthesis - Like plants and corals, they do well at low light levels for carbon fixation and will use available dissolved nutrients, and they have to deal with photo-damage from high light levels or UV. The coral symbiont is a dinoflagellate, so corals and dinos thrive under similar light.

Mixotrophy - many dinos ingest cells, parts of cells, or large molecules from other organisms to acquire scarce resources. They are very adept at rapid uptake of large organic sources of P and N, compared to other classes of algae that are better equipped to uptake small inorganic nutrients.

Storage - dinos store large amounts of P and N inside the cell – many times what the cell needs over its lifetime – and also use mucus mats & bacteria to lock up nutrients outside the cell where they are less available to competitor organisms.

Depletion of environment - dinos produce an extremely Carbon rich theca, that they shed every time they multiply. This is a form of carbon dosing that has been shown to deplete N & P through decomposition of theca. Once N & P are depleted, theca are unable to decompose, and accumulate in the system. The nutrients stay locked up in the dino bloom products, preventing healthy biodiversity until an input of N & P allows decomposition and normal biodiversity to progress.

The polysaccharide mucus mats produced are also Carbon-heavy and likely further the depletion effect. These behaviors are testimony to the ability of dinoflagellates to chemically reshape a system. This can be seen in the oft-reported difficulty of raising nutrients and stabilizing a system with an active dino bloom.

Low-Nutrient Triggers - Under low nutrient scenarios, dinos  employ increasingly aggressive chemical behavior through toxin production and reduced photosynthetic dependence while increasing levels of heterotrophy via consuming bacteria.

(Pics and vids) Large Cell Amphidinium with chloroplasts partially/totally destroyed by high doses of metronidazole. The cells continued to move, behave, and reproduce normally even without photosynthetic ability, as they shifted to heterotrophy. Exposure of these cells to weeks of total darkness also showed similar results.

Cell Defense

Cysts - If conditions fall outside the already wide range that dinos can thrive in, they can form a hard cellulose cyst (same material as theca), and remain in stasis for hours to months until favorable conditions return. Elevated temperature can induce cyst emergence, and is often a trigger for the onset of a spring bloom in the wild.

Toxins - dinos produce palytoxin and a range of related toxins to ward off predators, push out competitors, and kill organisms thereby freeing up nutrients through decomposition. Toxin effects are usually seen first in snail and pod lethargy and death, sometimes effects escalate to coral and fish loss. In the wild, humans are also affected directly by aerosolization and by magnification of toxins through the foodchain into consumed seafood. Hobbyist health has been adversely affected by these toxins (some have associated neurological effects), and absolute caution must be practiced. Notably, the transmission of toxins is associated with mucus and not limited to the cells themselves. Hobbyists frequently report an odor produced during a toxic bloom event.

Mucus and Strands - dinos produce mucus to form blobs, mats, or strands that provide some amount of protection from photo-damage, and also provide the ability to sink and form a weak-but-sufficient link to the benthos to avoid being washed away by prevailing currents. Strong surges and random flows can greatly disrupt a bloom population because of the insubstantial anchor. Mucus also allows them to colonize preferential locations, form strings to avoid contact with predators on substrate, discourage predators by distasteful and toxic mucus, control nutrient and organism movement in & out of substrate covered by mucus mat, and create media to grow bacterial associates.

Other Traits

Mobility - dinos’ flagella provide limited mobility, which is sufficient for the benthic species that form blooms in our tanks. Many cells typically leave the substrate at night when risk from currents and photo-damage is less. This daily vertical migration accounts for the cycle of blooms that look “cleaner” every morning, but “worse” every afternoon as cells return to the substrate. This motion may serve 3 purposes: spread to new locations, avoid active nocturnal grazers on the substrate, and chase nutrients.  

Ecology - dinos behave like annual species (bloom, seed, bust), are soloists -  domination of a single species at a time and place, are physically adapted to niches, are habitat specialists with multiple life-stage strategies tuned to the habitat, and rely on small numbers of bloom species in a location. (Diatoms are the opposite on nearly all counts.)  

The common experience of hobbyists with a tank overrun by dinos is a direct result of the ecological strategies that ensure dinos have an endless variety of strains capable of spreading and waiting invisibly in an environment for acceptable conditions and then exploit them to bloom to incredible densities.

Out of the 2000+ species of dinoflagellates, many hundreds make it into hobbyist aquariums, but only a handful or so have these traits necessary to cause problematic blooms in our tanks.

Types of Dinoflagellates

The Big 3

Ostreopsis

Top left and center: Ostreopsis populations. Top right: abnormal cells with red accumulation bodies compared to normal cells. Bottom Left: normal cells. Bottom center: cell division taking place within theca. Bottom right: cell either shedding theca to enter cyst state, or shedding short term cyst to resume normal growth.

Pics and vids 

The most common bloom culprit and accounts for the majority of tank losses due to dinos, can make long strands by combination of microfibers and mucus. Two types of cysts: short term - hours to days, or long term - months until warmth and nutrients are favorable. In wild, forms huge blooms covering macroalgae.

Amphidinium Large Cell

Top left and center & bottom right: Large Cell Amphidinium. Top right: outbreak on sandbed. Bottom left: Large Cell Amphidinium colonizing a cyano mat.
Pics and vids 

Brown dusty appearance resembles diatoms to the eye. Due to staying in/under sand, less susceptible to chemical kill methods than other species, and cannot be targeted by UV or other water filtration methods. Unaffected by extended darkness and metronidazole. Apparently susceptible to pressure from Macroalgae and associated grazers.

.

Prorocentrum Lima-like

Left: Prorocentrum. Right: Prorocentrum with Ostreopsis cells

Pics 

Least common of the “common” varieties. Can colonize any surface - even live copepods - by heavy mucus production. Swims almost identically to Large Cell Amphidinium, though frequently seen motionless in mucus.

Others Rarely Found in Aquaria

Amphidinium Small Cell

Top left & right: Small Cell Amphidinium with Large Cell Amphidinium. Bottom left: Small Cell Amphidinium with Ostreopsis cell center and Large Cell Amphidinium upper right. Bottom right: Mixed Small/Large Cell Amphidinium outbreak on rocks.

 Pics and Vids

Most active, fastest swimmer of our dinos and spreads easily to all surfaces. Has been reported to self-destruct by 9th day of darkness.

Coolia

Top left & right: Coolia cells. Bottom left: theca being separated from cell. Bottom right: Coolia outbreak on sand in a tank.

Pics and vids

 Very closely related to ostreopsis, and should be treated similarly.

Symbiodinium-like (no-ID)

Top left & center: Symbiodinium-like cells with a nematode - (center also contains a planktonic dinoflagellate - likely Akashiwo). Top right and Bottom left: Zoomed in view of cells. Bottom center: cells & mucus forming strands. Bottom right: cells & mucus forming blobs. Pics courtesy user NCreefguy
Pics

Motionless cells strongly resemble symbiodinium (zooxanthellae) embedded in thick mucus which allows long strands more characteristic of ostreopsis. It is unknown if these outbreaks are actually the coral symbionts run amok, or non-symbiotic species of symbiodinium found to hide in coral tissues, or an unrelated imposter dinoflagellate.

Others

There are 2000+ species of dinos so many different species could be present in an aquarium, but people’s reef tanks all seem to create similar conditions that allow only the same few species to bloom. If, however you have a non-standard system like no skimmer, then your tank will be habitable by a much wider, totally different population of dinos than those discussed here.

Treatment

In cases of a minor outbreak, many hobbyists have successfully ended the bloom by simply elevating nutrients and/or running UV. However, treatment of an advanced bloom should take a more holistic approach, and so presented here is info to address all of the effects of a dino bloom: Toxin content, Cell numbers, Nutrient Lock-up, Biodiversity, and Mucus Coverage.

Toxin Content

Signs of toxic bloom: pods or snails becoming lethargic, dying, or disappearance of pods and microlife. Accumulation of algae/dinos that the snails and clean up crew avoid. Coral polyp retraction. If any of these are observed, assume a toxic bloom.

The toxins are perhaps the biggest key to dino success in a tank and the associated struggles of the rest of the life in the system, therefore a constant effort to eliminate toxins should be ongoing with the rest of the treatment.

Fortunately all of the dino toxins we are aware of are thoroughly removed by granulated activated carbon (GAC). If you believe your bloom is non-toxic, run a small amount of GAC. If your bloom is toxic, run more GAC, and change more often. Additionally any actions that kill dinos in the tank should be accompanied by more GAC changes. Start conservatively - ½ to ¼  of the recommended amount and increase as needed up to full, based on careful monitoring of tank health. It may be better to favor more frequent changes instead of larger amounts of GAC.

Cell Numbers

The cells themselves are toxic and put any life that ingests or comes in close contact with them at risk. Lethal effects on benthic life tend to show up at cell densities of hundreds per mL – blooms are capable of local densities of millions of cells per mL. Additionally, cells under ideal conditions can increase their numbers by up to 60% per day, so a bloom can rapidly wreck a system if left unchecked. The final key reason to remove the dino cells is that cell removal also exports those trace elements that dinos particularly have high demand for. As soon as possible, action should be taken to manually remove the majority of cells, and an ongoing plan for automatic cell removal should be put in place.

Immediate mass removal

Siphoning - remove all visible dino material, while attempting to be selective (don’t remove healthy sand if possible). Remove Cyano mats, as they are often home to dinos which are hidden by the strong cyano color.

Blowing into Sock - use a turkey baster to blow them into a 10 micron sock. Only Small-cell Amphidinium or Symbiodinium-like are small enough to pass through this size. Don’t worry about spreading the cells to other parts of the tank - they are already everywhere.

Ongoing Automatic Removal

These methods target removal through the water column and use the fact that all of the dinos we know of except for Large-Cell Amphidinium enter the water column to some extent at night.

UV - run with slow flow (200-300 gph) placed inside the display tank (as opposed to the sump) has been found to be highly effective at cell killing for all tested species that enter the water column, and is particularly effective against ostreopsis. This method is strongly recommended. UV does not remove cells. It kills cells within the tank, so be aware of liberated toxins as well as nutrient lock-up. UV has the advantage of being able to run at peak efficiency for long periods compared to diatom filters.  A very speculative recommendation for UV size might be ~1 watt for every 2 or 3 gallons (the UV). No downside to going with higher power, except cost and increase in water temperature.

Filter sock -  (10 microns) can be helpful, but it may fill up too fast and not pass enough water through to be effective. If this is to be used, it must be monitored and rinsed frequently to ensure continued effectiveness.

Diatom filter - may be useful (~1 micron) but not a continuous-run filter. Has advantage of directly exporting even the small uncommon dinos.  Probably alleviates nutrient lock up compared to other filter forms.

Dino Scrubber (Filter Floss) -

Far left: filter floss rinsed and ready to go in. Center left: Dino Scrubber in action in minor ostreopsis outbreak. Center right: filter floss after a few hours of lights on. Far right: wring out from floss reveals near pure ostreopsis.

Credit to @Nvladik for this method. A very effective minimal-effort way to selectively remove large quantities of Ostreopsis dinos (and other species that colonize high flow surfaces - prorocentrum?). Take any rough netting or clothlike material such as filter floss with large surface area for dino attachment points. Hang in above average light in front of powerheads in high flow, during lights-on. Take out filter and rinse clean with FW once or multiple times during lights on period.

Photoperiod decrease - a few less hours of light can act as an environmental trigger to cause a larger percentage of the dino cells to go into the water column in search of better conditions. Therefore dropping the photoperiod from 10 hours to 6 to 4 to a 24-48 hour blackout can push progressively more and more cells into the water column. This can be especially useful when using UV on a toxic bloom and not wanting to kill the majority of toxic cells at once. Blackout longer than 48 hours is not recommended because it will have a harmful effect on the photosynthetic competitors of dinos, which are hopefully increasing in the place of dinos.

Blasting surfaces -  dislodging cells is another important tool to push the dino cells into the water column. It can be done during daylight, and as often as you feel like, but it is perhaps even more effective when done during lights-out while the environmental cue for the dinos already favors swimming in the water column.  

Skimming -  does not actually remove dinos in any significant number despite what many hobbyists would expect. There are other reasons to run or not run skimmer during treatment, but dino cell removal is not an important effect of skimming.

Nutrient Lock-Up

A dinoflagellate bloom is very effective at locking up nutrients Nitrogen (N) and Phosphorus (P) in a combination of dino cells, toxic mucus, and mucus-associated bacteria, leaving many other forms of life in the tank nutrient limited.

Remediation should start with a look back at the bloom’s history to attempt to determine what possible nutrient limitations that might have been present at the onset of the bloom still need to be fixed. Proceed with a full round of tests, especially for PO4 and NO3, and address anything that is clearly out of balance according to the tests. P and/or N are likely to be at or near zero – that’s too low. N & P targets aren’t the same for every system: some have found any amount of P above zero helps, other systems have needed to push PO4 to 0.10 or above before positive effects were seen. Knowing the tank history and nutrient levels leading to the onset of the dino bloom can help suggest target levels. But certainly measurable, consistent, non-zero N and P needs to be maintained to allow other classes of photosynthetic organisms to grow and compete and eventually (re)establish microscopic biodiversity. As outlined earlier, dinos have traits to outcompete many other forms of life in a system that is N or P limited. If however, N and P are readily available, resources that dinos are not as adept at competing for become scarce. In the short term, adjust N & P as needed with simple, inorganic liquid nutrients (KNO3, Flourish Phosphorus™, NeoPhos™, etc). Elevating nutrients by switching to heavy feeding is usually much less effective, likely because the organic forms of N & P are more readily uptaken by the dinos than by their competitors.

Within a few days to maybe weeks there should be signs of change in the bloom and the system – generally the bloom becomes less aggressive, non-toxic (edible to grazers), and slowly begins to recede, as other forms of life grow in the tank. Also watch nutrient levels carefully as the rates of uptake for elements will change as you add N & P and therefore change what resources are scarce in the system.

Do not be surprised to see some patches of algae growing in response to the nutrient changes. These are signs of progress, and should be treated as a normal part of the cycle.  See Appendix D: Algae Control for strategies of dealing with algae that are not associated with triggering dino outbreaks.

Remember that the way into a bad situation can also point to the way out – establishing a normal, consistent level of N and P inputs will make your system healthier, more resilient, and better able to resist invasive harmful algae blooms.

Biodiversity

Top left: briefly alive copepod covered in prorocentrum mucus/bacteria. Top center: munnid isopods grazing on amphidinium patch. Top right: trachelocerca? ciliate with ingested ostreopsis. Bottom left to right: Large euplotes, coleps, and hypotrich ciliates having ingested amphidinium cells. Click photos for link to pics and vids of dino grazers.

One striking microscope observation from advanced dinoflagellate blooms is the near total lack of biodiversity. Very little is present except for the dinos and their bacterial associates. Clearly this is achieved and enforced by dino activity, but it is also true that observations of media from ultra-low nutrient systems (ULNS) which are susceptible to dino outbreak show a similar biodiversity desert compared to media from a system with modest nutrient levels and inputs. Clearly dinos both thrive in, and create low biodiversity systems.

Although there are many classes of organisms (snails, crabs, fish) that likely interact with and graze on dinos incidentally, here we’ll restrict ourselves to three classes of easily overlooked micro-life that are not usually intentionally stocked, and have clear demonstrable effects: pods, ciliates, and bacteria.

Pods - “pods” here refers to copepods, amphipods, and munnid isopods. These all function as grazers of dinos and are limited by: toxins, predatory fish, lack of nutritious food (nothing grows on a dinoflagellate diet), and shared habitat (sand-dwelling pods will not affect dinos that form long strings high on rocks). Copepods are the most commonly cited grazer of dinos in the scientific literature, but their performance in a tank is usually ineffective. Likely this is because they are too small to effectively graze our problematic blooms of large dinos over 50 microns, and they are weak swimmers easily trapped by the dino mucus/bacteria. Amphipods on the other end of the spectrum, are huge, strong, indiscriminate grazers, and are not very sensitive to toxins. Munnid Isopods are also tough enough to avoid being killed easily by dinos, and interestingly, hobbyists report seeing increased presence of these grazing in and around dinos especially during the decline of a bloom. There would likely be more reports and more clarity if these weren’t so often confused for the more well-known copepods and amphipods.

Ciliates- although typically small, some ciliates grow large enough to ingest even large dinos and reproduce by splitting, so can increase in population much more rapidly than pods, and are not targeted by fish. In the scientific literature, ciliates are a known but rarely considered grazer of dinos, but for reasons listed above - in some of our systems they might be more important grazers than pods. Due to their transparent nature, it’s possible to confirm ciliate ingestion of dinos by direct observation.

Bacteria- bacteria can be either enemies or allies of dinos and nothing is yet known which would allow the hobbyist to distinguish between “good” or “bad” bacteria. There are bacteria that aid dinos by breaking down organisms killed from dino toxins and releasing N & P from the decomposition back into use by the dinos. Other bacteria are known to process and detoxify the dino toxins, and their presence can greatly lower the toxin content of a bloom. Bacteria can serve many other roles sustaining (or ending) a bloom also. It is therefore recommended that after removal of as much dino material as possible, an effort should be made to add bacteria to disrupt the population that has been established during the bloom.  

Algae- macro- and turf algae support dense populations of the organisms discussed above, and should be considered a sign of health in the system. Some macroalgae have also been shown to have chemical allelopathic effects that suppress dinoflagellate growth. Elevated constant nutrient input will promote this healthy algae growth. Macros can be manually imported into a system to combat an outbreak and manually removed afterward. This has been reported to be especially effective versus Large Cell Amphidinium as these non-toxic dinos have been seen to recede more rapidly in direct proximity to clumps of chaetomorpha. Algae-associated biodiversity is less effective versus toxic dinos, because the toxins protect them from the grazers that colonize algae. See Appendix D: Algae Control for ways to keep healthy algae in check.  

Sources of biodiversity- Other than purchase (Munnid Isopods not known to be commercially available), pods can be acquired from algal material and debris in the fishless fuge of a healthy system. This is also a good source of ciliates, but some sand and rubble from these healthy systems should be collected also, to get different ciliate species mix. Possible bacterial sources, in addition to those mentioned for ciliates, may include cultured skimmate.  See Appendix E: Culturing Skimmate  It is unknown if bacteria in a bottle products can positively disturb the bacterial population from a dino bloom.

Mucus Coverage

The mucus that is produced by dinos to form mats and strings contains toxins and distasteful chemicals to discourage predators. The toxic mucus can also irritate corals, and trap and kill much microlife, so removing should be part of the tank treatment. This is likely already addressed by running GAC for toxins, siphoning dino cells, blasting surfaces with flow, and increasing biodiversity.

Un-recommended Tools (potentially harmful)

These treatments have been documented to have some level of effectiveness at controlling apparent bloom size, but have either rarely or never led to a cured tank and are suspected of impairing recovery after the bloom. Their use typically results in decreased biodiversity, which allows the dino bloom to come back stronger than before. Some also have frequent reports of undesirable side-effects.

Although it may be theoretically possible to harness the bloom reduction qualities of these treatments and simultaneously mitigate the complex downsides, a more direct path to a healthy tank is possible without these treatments and so we recommend avoiding them altogether.

Oxidizers: Bleach, Peroxide, Ozone etc.

Antibiotics: Chemi-clean, Metronidazole, etc.

Algaecides: AlgaeFix, Vibrant (not technically algaecide, but has same effect), etc.

Dino-X: unknown mechanism, many reports of bad side effects, many non-responsive outbreaks

Prevention

Do not overstock a tank, or stock it too quickly.

Sudden changes in nutrients (usually an increase) that result from such stocking changes are what sparks most algae blooms. This often causes the hobbyist to take steps that are too drastic.

Feed regularly.

Regularly not more.  Feeding regularly, establishing consistent nutrient input is another thing that goes to promote general stability.

Do not use nutrient reduction tools on a new aquarium.

New aquariums appear to have very little reserve nutrients and thus seem subject to much quicker and more severe starvation effects.

Do not use phosphate removal tools on an aquarium that does not have an existing phosphate accumulation problem. 

Like in a new aquarium, there may not be sufficient phosphates in reserve so there is a possibility of doing harm.  A healthy system should grow algae somewhere.  Sluggish or no algae growth anywhere in a system should be a red flag, not a goal.

Do not use carbon-source dosing on a new, or nutrient-limited tank.

Carbon saturated environments are known to promote harmful algae blooms.

Do not use any of these tools (Carbon dosing, general nutrient reduction, phosphate removal) in excess or in dramatic increase.

The reefing proverb “Nothing good happens quickly” and the flip side - bad things can happen very quickly - is especially true in regard to harmful algae blooms. The organisms we want to have around can only adjust slowly, but dinos are well suited to exploit new conditions more rapidly than anything else in the system.

Glossary of Terms

Athecate - lacking armor (see amphidinium)
Benthic - bottom dwelling

Bloom - A large growth of a population of algae under favorable conditions.
Cyst - a resting state of the dinoflagellate that is not motile, and sometimes has a double thick wall of same material as the theca, often in response to unfavorable conditions. Known cyst types: short term - to deal with brief unfavorable conditions, long term - for overwintering until next growing season, and sexual - for multiple divisions to occur with DNA exchange.

Epiphytic - grows attached (as epiphyte) on surfaces such as macroalgae

HABs - Harmful Algae Blooms, catch-all term for large population density of any algae (dinoflagellates, cyanobacteria, diatoms, etc) that causes a harmful water quality condition

N - Nitrate (NO3)

P - Phosphate (PO4)

Phototaxis - a migrational movement based on light, either toward or away

Planktonic - living suspended in the water

Theca - cellulose armor (high carbon source) covering most dinos, made up of plates with distinctive shape. Plate structure is often used to define species

Thecate - a dino with armor

Appendix A: Quarantine

Hypothetically, individual animals or plants could be quarantined according to methods used for another pest dinoflagellate: Amyloodinium, aka Velvet.  However the question would be about efficacy: the QT time period is specific to Velvet and we have no idea (currently) if it would be as effective against our Genera of dinoflagellates. We know dinoflagellates don’t always share a lot of similarities and are often different even within their similarities.

But ecology of the tank may be a bigger problem than external vectors.

Typical dipping processes (Freshwater, dilute peroxide) may alleviate attached dinoflagellates to a degree.  Going into a healthy tank, this should be sufficient.

Treating dinos as ever-present and dealing with them through husbandry and tank conditions has shown success. Reefers with healthy tank conditions – meaning well-fed and well-developed microbial diversity – import livestock and even wild collect without dinos (or, notably, other critters) taking over their system.

Appendix B:  “Zero Nutrients”

One of the two most common background stories among dino sufferers is that in the process of fighting another algae problem they aggressively dropped the levels of phosphate (P) and nitrate (N) in their tank and try to hold them at or near zero.

The variant of that story is that they’ve done that systematically for the whole life of the tank.  (This seems to be the most direct way to get a bad algae bloom.)

They could have used GFO, lanthanum chloride, organic carbon dosing, etc.  GFO+carbon source is a very popular combination.

Somewhere during or after treatment, a weird brown, slimy, bubbly, sometimes stringy “algae” takes over.  Dinoflagellates!

It’s noteworthy that protein skimmers, macro-algae refugiums and “algae turf scrubber” (ATS) filters are the more popular methods of nutrient control that are NOT associated with dino outbreaks.

Appendix C: Sometimes Confused for Dinos
Cyanobacteria

See pics. People often ask “cyano or dinos” and the truth is many times it’s both - dinos, especially amphidinium, are often very comfortable growing in cyanobacterial mats.

Spirulina

Click on pic for link to video

Technically, a kind of cyanobacteria, with some differences in structure and behavior from the common cyano.

Diatoms

Photographic Key

Diatoms are an immense group with too many possible forms to show representatives of them all. Pictured are some pennate (pointed) diatoms, which are more common in reef tanks than the centric (round) types. They usually appear the same color as dinoflagellates and some are even capable of forming stringy filaments in the flow. Under a microscope, they can be distinguished from our problem dinos by their sharp pointed shape and by diatoms almost total lack of movement.

Ciliates

Pics (Google Images)

Photographic Key

Fast swimming aggressive tiny predators. A welcome sight as large ciliates are known to ingest dinos. They are named for the cilia (small hairs) that they use for both movement and for feeding.  

Chrysophytes

(forum thread link?)

Very little is known about these in reef tanks, but a few instances are beginning to be reported by hobbyists.  Some in-tank blooms have been associated with salinity spikes.

Appendix D: Recommended Algae Control Methods

ATS

Fuge

Increased/better grazers

Appendix E: Culturing Skimmate

Credit to user MontiReef for this approach. 

The purpose of this method is to generate a large population of heterotrophic bacteria that are not associated with a dino bloom and are therefore hopefully antagonistic to the bloom mechanisms rather than supporting them.

Dump the skimmate including all the solids and gunk into a container, and allow it to sit aerated and lit for several days to a week until the skimmate noticeably lightens - (like when a culture of phytoplankton goes bad and lightens rather than darkens). It is likely beneficial to run a slow bubbler and light on the container to encourage organisms that can survive the lit, oxygenated environment of the reef tank.

Credits

“A cell of Ostreopsis cf. ovata, sampled in the Gulf of Naples (Tyrrhenian Sea, Mediterranean Sea).”

Wikimedia Commons File 

Image in use is cropped from the original.

By Cybergerac (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons

“bioluminescent dinoflagellates producing light in breaking waves”

Wikimedia Commons File

Image in use is cropped from the original.

By catalano82 (Red Tide Luminescense) [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons

“field sample of Prorocentrum lima”

Wikimedia Commons File

Image in use is cropped from the original.

By Cybergerac (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons