For this article, I have taken a different approach to the format schematic compared to my other research topics. We at ReefNation have teamed up with an expert on the topic of cyanobacteria, Mr. Todd Williard. He has helped answer many questions that we feel are substantial in understanding and combating cyano, and measurements to take care of it if cyano does pop up in an aquarium setting. I have created a Q&A interview between him and I on what we felt were the most vital questions to ask for people who are in the saltwater aquarium hobby. A link to his forum thread about this topic is cited below, so please check it out after reading this article for further information.


What is Cyanobacteria?

“Cyanobacteria is a blue-green bacteria which utilize photosynthesis as a primary energy source. They form long multi-cell strands releasing O2 as a byproduct. It is believed that cyanobacteria is responsible for our current atmosphere. They reproduce by cell division and separation.”


What does Cyano look like?

“Cyanobacteria in the most common situation will form a rust colored thin mat that will sway with the water current. Easily removed by siphon process. This bacteria may also appear in other forms of color such as green. They all will produce o2 bubbles that become trapped under or within the thin mat created.”

What should people look for if they have an outbreak of it?

“The best indication of the beginnings of cyanobacteria is the formation of o2 during the formation and growth. Small thin strands of cyanobacteria will start to form in low flow areas as a rust red, green color involving an o2 bubble at the end raising it up off the surface. A tank outbreak will include several large sections of cyanobacteria growth.”


Does Cyano harm coral and other species in an aquarium?

“Cyanobacteria is non-toxic in nature. The majority of cyanobacteria formations is the anaerobic conditions produced under the thin layers that are formed. These conditions will void the areas of O2 resulting in loss of coral or microscopic life creating the toxic environment underneath.”


How does it get introduced in an aquarium?

“Cyanobacterium’s through the course of studying its biological life cycle must be introduced into our enclosed systems. This would be from the addition of corals, fish and inverts. Care must be taken to properly QT all incoming specimens to aid in the prevention of introduction into the main system.”


What is the best method of treatment for it?

“The best method for the common Cylindrosperum sp. Cyanobacteria is the use of 3% hydrogen peroxide dosed at 1ml per 10 gallons of tank volume every 12 hours for 14 days. There are other methods of treatment but this common form has been found to be resistant to other forms of treatment.”

If established in an aquarium and cured, can it come back similar to algae?

“Through my work I have not found evidence of re-population of cyanobacteria even through attempts of revival. The method of treatment explained above does irreversible damage to outside layers of the cells rendering the cells thylakoids unable to produce the energy needed from photosynthesis.”


 Are there any long term detrimental effects with cyano being in an aquarium?

“There are no long term effects from the bacteria itself. It can be present in controlled populations. The only long term issue with cyanobacteria is caused by the anaerobic conditions caused by the lack of water flow underneath causing high levels of dioxides which is toxic to the environment.”



Mr. Williard would also like to point out that there is a similar strain of bacteria called spirulina, which can be almost identical to cyano. This can actually be used as a dietary supplement among humans and found at your local health food store. The treatment for spirulina is completely different than cyanobacteria, and most of the time only experts can distinguish between the two bacteriums with the use of a microscope to see what is going on at a cellular level.



Todd’s Forum: