The cyanobacteria you have resembles Pseudanabana, but your image lacks enough detail. You also have diatoms and greens in this image.

I'd call in the cyanobacterium Leptolyngbya. It is not considered toxic. Other than sterilized cultures and removing all light and nutrients, you would likely need a chemical treatment. CuSO4 could work at concentrations that don't affect mysids, but you'd have to test that hypothesis.

Maybe Phormidium with some Chlorella. As Barry says, you need a better image AND a description of the environment from which it has been isolated. I do not know the diatoms splashed around.

It´s like Geitlerinema (filamentous cyanobacteria) if it has moving.

Leptolyngbya is another possibility, but a higher magnification image would be necessary.

The green filament looks like a filamentous cyanobacteria, Leptolygbya or a thin Phormidium. There are also green algae and diatoms.

Mariona Hernández Mariné

In principle are not harmful.

plz upload good images, so we can see the details of the cells otherwise everyone thinks and assumes. And assumptions are not true every time. so for correct identification needs good quality photo or image

No doubt it was an algae ... but without seen the cell structure and their arrangement we cant say anything

look like Oscillatoria which is unbranched filamentous cyanobacteria with mucilaginous sheaths, but I think you should take picture with higher magnification and focus on one filament

Dear David, this is a mixed culture of Cyanobacteria (Phormedium+Anabaena+Spirulina).

Apart from cyanobacteria, there are some green algae species like scenedesmus and chlorella. Definitely not harmful

it seems to be a lichen: fungine ife with unicellulare algae like trebouxia. It beginns to grow up in this way.

If you have enough biomass for DNA extraction, it would be feasable to amplify rRNA sequence and then you can have a clear cut as to what they are. Of course a quick answer could come from a clear image for a higher magnification field. DIC or phase contrast microscope availability would even give you a better contrast image. Good luck

Hydrogenperoxide in the ppm range will kill cyanos while not harming eukaryots.

Good luck, René

These are algae, filamentous and unicellular. However, this resolution is not good enough to identify what they are. I guess they could be Planktothrix or Oscillatoria (for the filamentous algae), and Microcystis or Chlorella (for the unicellular algae).

Maybe you could try to get some other cultures out of the aquaria, and put the aquaria in a dark room to kill the algae (?). And some kinds of algaecide may also be helpful.

This looks like simple green algae, however the slide is not a very clear image. If we could see the structure of the filaments, better identification can be given. Most green algae isn't harmful.

Another look at your photo seems to show that there is a mix of Oscillatoria and possibly Anabaena. I noticed the large green mass on top of your slide, was there any brown algae in the mix as well?

Oscillatoria (the large mobile filamentous thing), Chlorella (nice little green balls), some pennate diatoms (Rhombus shaped), a few flagellates and a green fuzzy filamentous celled thing that could be anything.

Dear David,sure its a mixture of various kinds of algae including filamentous cyanobacteria like Phormidium and Oscillatoria and even few unicellular forms.

The cloudy upper portion of your photomicrograph may have some fungal mycelium. I could also notice few diatoms (could be Navicula and or Pinnularia). I suggest a molecular characterization and Biochemical analysis (if you have enough biomass) if you are particular in the identification of its species and its harmful components.

I don't think all of these are harmful.

Cutting off light could be a simple step to stop the algal growth.

It is Oscillatoria and other blue green algae, mostly. Innocuous but if you want to remove, try reducing the light intensity ~20 uphotons/m2/s or increase dark part of photoregime. 200 mg erythromycin phosphate/10 gallons water might work too. All the best!

The picture is not very clear, but the filamentous mass is cyanobacterium from the family Pseudanabaenaceae, very probably some Pseudanabaena species. It is not Oscillatoria, Anabaena neither Phormidium because o thallus morphology. The type should not be harmful.

Cyanobacteria may be Anabaena sp.

Filamentous algae seems like Pseudanabaena sp., Limnothrix sp. or Symploca sp.. Need a clear image and scale bar to identify it correctly.

I see a mixture of algae/cyanobacteria here:

a filamentous cyanobacterium, maybe Microcoleus spec. or Phormidium - typical biofilm algae. And there are some coccal green algae and maybe some pennate diatoms and euglenophytes. Most of them are usually non toxic. You may try to lower the trophic status in your aquarium and higher the light intensity to harm the cyanobacteria. But you will probably end up in enhancing the growth of green algae or others if the cyanos decrease. More exact identification would need a magnitude and higher magnification.

Thanks to everyone for the very usefull input. I tried to make a better picture of the cyanobacteria.

And another picture. Decreasing the light intensitiy would be a good option but I can't make it 'dark' as my animals would not like it. I guess that I'll just have to clean it as long as it is not harmful. ps: the scalebare is not correct, i'm sorry for that.

Dear David,

This seems to be Oscillatoria sp. (the filamentous cyanobacteria). And I can see a green algae - Chlorella sp. growing in abundantly. Also, diatoms are growing in the culture (probably Amphora sp.). You may keep the culture in dark or check (limit) the nutrient quality of the medium to avoid them.

Best

Dola

Again, these algae excrete polysaccharides and encourage bacterial growth in the culture medium.

maybe it could be a Lyngbya, marine cyanobacteria, their cells are shorter than long, always in colony with mucilage

This scale of this picture is by far to small to be able to identify properly. The filamentous material is a cyanobacterium of the Oscillatoriales group and the green unicells are green algae, diatoms also occur. However, not enough detail can beseen of the green algae to even have a glimps of an idea what genus it could be.

Best regards,

Burkhard

I cannot contribute more to the species determination but if you want to get rid of the algae you have to either reduce light, reduce the phosphor contentration or you increase the grazing pressure on the algae. Maybe just a few snails help you if the algae grow mostly attached to surfaces ....

If it becomes a nuisance, 2ppm H2O2 will get rid of all cyano's, without harm to anything else (check Matthijs 2012).

May be Oscillatoria sp. or Lyngbya sp. (the filamentous cyanobacteria) and a green algae - Chlorella sp.

Can the experts recommend some literature to identify such (tropical) filamentous algae? Thx!

This picture dominates with the growth of a common non-heterocystous filamentous cyanobacterium Phormidium tenue or Phormidium fragile, however as per recent nomenclature this cyanobacterium would name as Leptolyngbya tenuis or Leptolyngbya fragilis. Detail morphological analysis would require to make sure which one of these two names is correct. Either of these two are not known as pathogenic or toxin producer, however under eutrophic conditions some cyanobacteria produces toxins. This cyanobacterium has tendency to grow faster than any other contaminant seen in this picture and it forms green biofilm. It is very difficult to selectively kill this cyanobacterium because it grows almost in all conditions of light, salinity, temperature, pH, nutrients etc. Best thing would be to bleach the tank keeping your other aquarium animals away for a while and re-introduce later to the clean aquarium tank. In this picture, few diatoms are seen but for green cells, it may even be some cyanobacteria that needs detail micromorphological analysis.

Dear David, its very interesting to see such growth of various algae. but the picture is not very clear to me. kindly upload picture of a single filament in 10x100 magnification.

This is a homocytous cyanobacteria (subsection III) previously Oscillatoriales.

It is probably not a Pseudanabaena because this genus usually exhibit trichomes with marked constrictions and polar gaz vacuoles. The polar gaz vacuoles, often difficult to see within the trichome, are generally well visible at the end of the trichomes as a refringent granule. This is not seen on the picture

Indeed a better picture with a scale and also indications on the motility of the strain are needed, but with regard to the size of the trichomes, the determination as Phormidium tenue by Sushanta Saha seems quite possible.

For future identification use C. Mervin Palmers "Algae in water supplies" as a key to identify algae

Thanks Haider!

I found that this book is available online via the UNT online library:

http://digital.library.unt.edu/ark:/67531/metadc9129/m1/1/

That's awesome you found it!! The book has illustrations as well as a key in the back to identify unknown alga

Very poor...

The reference for procaryotes taxonomy is the Bergey's manual

I recently found that the chaper on cyanobacteria is available on the web, unfortunately without drawings, but the key are helpful.

Just search for: "bergey's cyanobacteria"on the web

Thank you all for your answers. I know my photo is not really top quality but it does seem that this is the best I can get it ... , I'm glad to see that most of you agree that it is a non-toxic algae/cyano.

Some of the filaments are mobile however the pictures here are stacks of pictures taken in a 2 minute timeframe so most of them do not move.

The picture is quite clean, however it requires further magnification. For proper identification the movement of cells under the microscope is also requireded to be observed. Its a mix culture contains both cyanobacteria and algae. The predominant species is cyanobacterium appears as Phormidium sp. The alga appears like Chlorella sp.,however it cant be confirmed. If the algae is moving in a semicircular path, then you can predict it as Chlorella sp..

I think it's Phormidium. Most likely not harmful.

On the basis of its morphology It looks like Phormidium sp. However, molecular phylogenetics studies show that phormidium is not monophyletic. A complicated lanscape. See

https://www.researchgate.net/publication/229720152_POLYPHASIC_STUDY_OF_ANTARCTIC_CYANOBACTERIAL_STRAINS1

https://www.researchgate.net/publication/251119111_Phylogeny_of_Cyanobacteria_An_Overview

http://sandwalk.blogspot.com.ar/2013/07/contradictory-phylogenies-for.html

Article Polyphasic study of Antarctic cyanobacterial strains

Article Phylogeny of Cyanobacteria: An Overview

More... See Algaebase: "Thomazeau et al. (2010: 575) note that Phormidium belongs taxonomically to the most difficult cyanobacterial genus and that the type species P. lucidum is subject to controversy (Komárek & Anagnostidis 2005)".

http://www.algaebase.org/search/genus/detail/?genus_id=43079&sk=0

You can also ask for the following paper in RG

https://www.researchgate.net/publication/227750316_THE_CONTRIBUTION_OF_SUBSAHARAN_AFRICAN_STRAINS_TO_THE_PHYLOGENY_OF_CYANOBACTERIA_FOCUSING_ON_THE_NOSTOCACEAE_%28NOSTOCALES_CYANOBACTERIA%291

Article The contribution of Sub-Saharan African strains to the phylo...

The image is too small to make a good family call-likely Pseudanabaceae. I would like to get some of this material-we are working on a toxin-producing alga from mysid rearing facilities if you wish to share. [email protected]

You need to use Komarek's 3 volume Reclassification of cyanobacteria-third volume was just published. FYI a number of Geitlerinema produce toxins based on Brazilean isolates! We will be naming a new marine genus and species for our toxic strain as it does not match the size or thylakoid arrangement of other genera.

Difficult to say without rular in image

I think it is cyanobacteria group, it is not harmful algae.