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Algae classification help please

5516 Views 34 Replies 5 Participants Last post by  Bucha
Actually, I am making a LED light fixture. To make a fixture that discourage algae growth, i am looking to learn about algae photosynthesis, so scientific names are needed. Below I tried to compile the list of common algae names + scientific names + descriptions. Will you please check and correct this list. It will be greatly appreciated.

I took the general organization of the list from
and did changes and corrections, so just giving the credit to this Ukrainian site.

1. Coatings of dust or mucus

1.1. Diatoms = Bacillariophyceae, Bacilariophyta. Do NOT belong to Brown Algae
Dense coating of brown or brown-black dust on soil, plant leaves, glass, is easily shaken off by fingers or a toothbrush.

1.2. Blue-green algae, BGA = Cyanobacteria = Oscillitoria splendens, Lyngbya, Anabaena? Aphanizomenon?
Coating is similar to a thin film that may completely cover leaves or soil. It is separated as a whole mucus-like layer, with a specific unpleasant odor. Color from light green to black with a purple tint.

1.3. Green spot algae = Xenococcus kerneri sp., Cyanobacteria; Coleochaete orbicularis sp., Charophyta
Very strongly attached, round, light or dark green spots on the glass, leaves of slowly growing plants, and decorations.

1.4. Green dust algae = Chlamydomonas Genus, Chlorophyta; Protococcus Genus, Chlorophyta
Green, thick, slippery to the touch dust coating on the walls of the aquarium. Initially appears close to the lamps or aeration. Leaves of plants mostly remain clean. Easily removed by a scraper.

2. Long (over 5 cm) thread-like algae

2.1. Silk algae, Water silk = Spirogyra Genus, Charophyta
Long, non-branching, light green, very thin, filaments that can extend from the tops of plants through the entire aquarium. It expands quickly, forming dense cotton-like bundles that feel slippery and slimy to the touch. Outside the water, they appear as a continuous homogeneous mass, easily crushed by fingers.

2.2. Horse hair algae = Pithophora Genus, Chlorophyta
Very long, coarse, dark-green, brownish-yellow or brownish-green threads, solitary, or as a bundle with a texture of steel wool. Each thread is attached at one end, the threads seem to be growing from a single point. Easily removed on pulling. On the longest threads, there are noticeable single thickenings ("beads"). Outside the water you can see individual threads that are very hard.

3. Short non-branching filaments

3.1. Hair algae = Oedogonium Genus, Chlorophyta
Thin, short, green threads covering plants, stones or driftwood and giving them a special fluffy appearance. Each thread is attached separately, but overall it looks like a rug.

3.2. Fuzz algae = Rhizoclonium Genus, Chlorophyta
Short, very soft, slippery to the touch, light green to brown filaments bunched into bundles that resemble cotton wool. Outside the water they become a homogeneous mass. First appear on the ground or on ground cover plants.May look similar to Spirogyra, but the threads are shorter.

4. Short branching filaments

4.1. Black beard, Black brush, BBA = Audeuinella Genus, Rhodophyta
Branching, sufficiently large, very fast growing, gray-green or black filaments first appear along the edge of the leaf from a single origin, then spread along the entire leaf blade, and quickly hit new leaves and substrate in the aquarium. Rarely on glass.

4.2.Staghorn algae = Compsopogon caeruleus sp., Compsopogon iyengarii sp., Rhodophyta
Black or very dark-green, 0.5-2 cm relatively thick and hard semi-transparent strands, growing as bundles from a single origin, first along the edges of the leaves, then rapidly assemble and form a solid black mat. Rhizoids grow into cells of plants damaging them.

4.3. Blanket weed = Cladophora Genus, Chlorophyta; C. glomerata sp.?
Threads branch strongly and visibly, bushy growth resembling moss. Usually grows on the substrate and wood, can form free-floating mats, may attach to slowly growing plants. Outside the water, the structure is quite stiff, rough, has a specific smell.

5. Floating algae
5.1. Green water = Microcystis Genus, unicellular cyanobacteria, and green Euglenophyta
The water in the aquarium becomes green, while plants and soil often remain clean, but may develop a touch of green and feel slippery to the touch.
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I did not know there are blue-greens with sturdy filaments (roll into a ball, rather than crumble when rubbed). What are the features of your "beard cyano" that tells you it's a cyano? Are short cells (like stacked disks) a cyano feature?
My husband gave me a book as a present: Freshwater Algae of North America, 2nd Edition
From the photos in the book it seems to be filamentous Cyanobacteria.

About my "half-leaf" identification: it is indeed Oscillatoria. Yesterday night I put it on a microscope slide in a dark room and shined a strong light beam from a flashlight on the side of the slide. After 10 minutes of wait, the filaments began to slide over each other moving toward the light. To the best of my current knowledge, it is a unique property of Oscillatoria.

I failed to see any movement of filaments in the same experiment with this new algae, but will try again tonight.
That's a good husband. I suggest you keep him. I'm always amazed how Oscillatoria seems to crawl around in a container after I peel sheets of it out of my tanks. Does your book explain HOW it does this?

Here's a few free downloadable Freshwater Algae ID references (if you don't have Bucha's book): (Bellinger & Sigee 2010)
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Yeah, have kept him for 30 years, since we were very young, through thick and very thin...

I have not found the explanation for the moving in the book yet, the language is very Phycology-academical, so I am still learning it. I have written to several Phycology professors I could find online, including one who is responsible for
So far I got only one reply "I do not have knowledge to help, buy I believe X can help", which I think was a very kind and wonderful reply. So I will write to X today.

I have also posted the last photos on
but no one replied.

I tried again and failed again to see any moving for the last specimen...
I'm trying to grow green water in a liter bottle outside. I put in pond water and all I have so far is a small amount of dust algae. I'm trying to figure out what nutrients triggers these diatoms. I just put in a pinch of micronutrients to see if this is the trigger. If not, next would be the macronutrients.

You should look at diatoms under the microscope. They're beautiful.
I would love to! But I do not have them now (my otocinclus love to clean them, probably tasty to them) and could not get decent samples from stores. If you send me some, I would definitely try my best to get decent photos and post them here. I am in Colorado.
Try a swipe from inside a filter tube or other place that Oto's can't get to.
I can take a photo for you. I have a microscope also.
mistergreen: yes, please
Gerald: thank you, I will try

Everyone: I got a reply from the author of "Filamentous Cyanobacteria" chapter from "Freshwater Algae of North America" book. He says about the CyanobacteriaX photos posted previously: "I think this is a tropical species. It is certainly Nostocales." He also thinks that most likely "The alga is in the Scytonemataceae", the genus may be Scytonema

To organize it:
Phylum: Cyanobacteria (4,637 known species)
Class: Cyanophyceae (4,637 sp., of which 65 sp. identification is uncertain).
Subclass: Nostocophycidae (1,472 sp.)
Order: Nostocales (1,472 sp.)
Family: Scytonemataceae (180 sp.)
Genus: Scytonema (130 sp.)

Yes, we do have an least two types of bearded Cyanobacteria in our tanks! May be they can be controlled by lighting and antibiotics? I will investigate this and post on my light thread. Should this algae thread, indeed, be "sticky-ed"?
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I'm against using antibiotics to treat algae. It should only be treated for fish disease. You'll create resistant strains of diseases otherwise.

A dose of 1ml/Gallon of Excel will pretty much kill algae and sometimes fish. I guess you can go .5ml/G as instructed on the Excel bottle. Using glutaraldehyde has its downsides also.
Agreed that antibiotics should be the very last resort. Still it is nice to have this resort.
Don't go bashing blue-greens without knowing their full story ... (this is the "beard" one Bucha found on the plastic plant).

"Scytonema is an example of one of many genera of cyanobacteria (blue-green algae) that are classified as free-living nitrogen fixers. Considered to be one of the most primitive autotrophic organisms on the planet, they are credited with converting earth's atmophere from an oxygen-free to an oxygen-rich environment, and thus setting the stage for the evolution of aerobic organisms. Embedded within the dark filamentous portion of the blue-green algae pictured to the left (see white spots) are heterocysts: structures devoid of oxygen to allow the enzyme nitrogenase to fix atmospheric dinitrogen (N2) into ammonium (NH3). Heterocytous cyanophytes can flourish in environments limited in nitrogenous compounds in that they can supply their own fixed nitrogen (Schlesinger 1997). It has been demonstrated that nitrogen fixed by free-living, heterocystous cyanobacteria bacteria is transferred to higher plants, and in an experiment using labelled 15N (see following diagram for details), Bentley and Carpenter (1984) demonstrated the transfer of fixed nitrogen from epiphyllous cyanobacteria colonies to the host leaf in a Costa Rican forest. "
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I added micros to my pond water and 24 hours later, the water is brownish, probably brown diatoms. I'll pop out the microscope to see what it is... I'll add macros to get green diatoms hopefully.
I have made a mistake, the "half-leaf-alga" is not Oscillatoria, it is actually Lyngbya (a closely related blue-green alga)! This explains why it rolls in a tight ball, while, as Gerald pointed out, Oscillatoria probably should turn to dust in your fingers. As a professional pointed out: "They (Lyngbya) look like Oscillatoria, but have distinct sheaths, evident in your pix where the cells have retracted or broken out of the sheath."
Gerald is also right about the nitrogen fixation by many cyanobacteria, namely those belonging to order Nostocales.

A very interesting thing happened. A professional has looked at my Scytonema pictures and noticed the bunches-like branching at the top of the picture named: "Two types of cells in the same filament and pseudo-branching of cells type 1". He told me that Scytonema is a non attached alga, and these branching on the top of the photo belongs to Tolypothrix. So I washed the piece of this plastic plant, got rid of non-attached black-cotton-ball-like Scytonema, and there was Tolypothrix actually attached to the plastic of this artificial plant! Another Black Beard! So the photos of Tolypothrix are below. The false branching in Tolypothrix occurs at one or more heterocytes (formerly "heterocysts"), which are the sites of nitrogen-fixation that Gerald wrote about. You can easily see them (bright green) in the last photo. On the second photo you can also see a tiny (reddish-colored) piece of Scytonema for comparison of these two algae.

An easy way to subdue any nitrogen-fixating Cyanobacteria is to keep nitrates above 20 ppm for two weeks. I tried this twice in my life it and it works. Also, Cyanobacteria does not like 1 ppm of Manganese, which does not bother the rest of aquarium habitat. So finding the third cyanobacteria-beard is good news


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