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Algae classification help please

5511 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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is it even possible to make a LED with the instruments and tools we have in this day and age that only gives certain wavelengths to certain plants?
Green algae and plants use the same light wavelength. There's no magic solution to algae. It's part of the ecosystem. Just have lots of plants and clean moving water to control them.
Some of most unpleasant algae are Rhodophyta and Cyanobacteria, the last do not even have Chlorophyl B! So it IS possible to control them with lighting, I will be posting details soon on Lighting post.
The other thing you should consider is if it looks good to the human eye. Sure you can just run red and blue led but your tank would look like a rave.
BBA is horrendous though. The other algae are pretty easy to control.
Very nice start! I like your descriptive categories. Some categories include additional algae genera not listed. "Green water" for example could include many other genera from several orders. Phormidium is another of the common slime-forming BGs, nearly identical to Oscillatoria. "Long" and "short" categories may overlap, since flow, nutrients, hardness, season, and other factors can influence growth form. Whether it helps or not in getting RID of algae, I like knowing what's growing in my tanks and tubs. This will be a useful guide. Here's another interesting site that might help:
Thank you, everyone!
I went to a neighborhood aquatic store, asked for an anubia leaf with algae that looks like BBA to me. Attached are a photo of the leaf and microscope photos at 2 magnifications. It is definitely Audeuinella, Rhodophyta. But the algae does not turn red in acetone or alcohol. It it a myth that BBA should? Also, does it look like BBA to you or like Staghorn or anything else?

Administrator: why my HTML code is off? I can not make "bold" fonts, enter pictures in the text... I wanted to post some useful graphs about lighting...


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Also I collected dome definitely Green Dust Algae from my tank and attached below a photo with maximum magnification possible on my very old cheap microscope. It does not look similar to photos of Chlamydomonas (Chlorophyta) OR Protococcus (Chlorophyta) that I can find. In my tank I MAY BE have some Actidesmium. Does not mean that others are wrong, there may be several species. I an NOT a biologist. Now I have just put a microscope slide in my tank and hope to grow some Green Dust on it, hopefully it will allow to make a better and undisturbed photo.


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wow thats awesome!
Looks like BBA/red algae of some sort. It turns red over time, like a day or 2. I've never seen it turn red immediately. In pure bleach it takes 15 minutes to turn red and then white.
OK, I have found some Green Spot in my second tank and it is DEFINITELY Coleochaete! The question now is which of 22 known Coleochaete species...
Never expected to actually be searching for algae in my tanks :)

Attached are:
1. A photo of Green Spot Coleochaete with some yet unidentified Green Dust (growing it, will post if successful) on the sides, so you can compare the sizes.
2. The same slide let to dry for 15 min without moving it, the resolution seems slightly better.
3. Baby Coleochaete to prove that the Green Dust cells on the previous pictures does not belong to Green Spot algae natural assembly in the middle.

DuthMuch: I am just lucky because my husband works on a lathe, so we took our old cheap Kodak EasyShare C913 and machined it to fit the microscope on the top of ocular.
Gerald: thank you so much for the link, it will help A LOT!


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I have read that black algae are really red algae. Human eyes are not good for red colors, so that may be why some "red algae" looks so black to us.

Also, green dust algae is a free swimming algae in its relatively early stages. When we wipe it off the glass, into the water, it just swims around until it finds another suitable place to homestead.

With that I have almost used up my entire bank of knowledge about algae!
that is just.... So cool.
Can mods pin this thread cause its Actually important information?
@michael @hoppycalif

Or maybe the OP can make a separate thread onces she ID's all algae's and their place in the chain of species and then pin that (easier)
I went to a very greedy aquatic store. I gave them a beautiful Bucephalandra with >10 leaves, they gave me half a leaf. I was asking for a whole leaf...
Two photos of the front and side of this half-leaf are attached, as well as three microscope photos at two magnifications.
In 99.9% when people think that they have made a discovery, they are mistaken. However, the only identification I could propose for this case is Cyanobacteria from Family Oscillatoriaceae. According to Algaebase this family has 3 major Genus: Oscillatoria, Lyngbya and Phormidium.
After hours at the microscope I did not find a single branching or a single sporangium (a sack with spores), so it could not be Audeuinella. It is to small and, again, not branching for Compsopogon. All filamentous Chlorophyta seems to have visible walls between cells, I could not see any. So while looking like a "beard" this algae very much resemble filamentous cyanobacteria, most likely Oscillatoria. Yellow Beard Algae?


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"I am NOT a biologist." I disagree; that's just not your paid job. Nice microscopy work, and your research and observational skills and healthy skepticism of conventional claims are on par with many good biologists. Aquarium-grown algae can sometimes have different growth forms, colors, and even cell morphology compared with wild-collected ones of the same kind. There's a few easy-to-ID algae groups, like Audouinella, Chara, and Oscillatoriales (if you're willing to settle for Order level) that are recognizable based on color, growth form and texture, and hundreds of others that are really tough to ID without a good microscope and Phycology books. I had one intro Phycology class 30 yrs ago; wish I knew more.

Agree with "most likely Oscillatoria" (or at least Ocillatoriales order) for the stuff on the leaf above above. Oscillatoria crumbles easily to dust when you rub it, unlike many filamentous Greens. But there's also filamentous diatoms that do that.
"i am not a biologist." i disagree; that's just not your paid job. Nice microscopy work, and your research and observational skills and healthy skepticism of conventional claims are on par with many good biologists.
Guys, you are too kind! It is the first forum I have ever joined, and people are just nice!

Here comes some beautiful Staghorn = Compsopogon caeruleus. It is HUGE under microscope, the branching is easily seen with naked eyes. Probably the easiest way to distinguish it from BBA is this visible branching. The very tip of the largest branch on a close-up is a little broken by me, still the overall shape of the bulge on the tip is visible. Will try again tomorrow.

I have found a store in Denver with wonderful people, they give me whole leaves and actually help to search for algae in their store, so more photos are coming!


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I have found another filamentous cyanobacteria resembling a beard. The first (half a leaf) and this one are found in aquatic stores 30 miles apart, in two cities, which get their tap water supply from different sources.

This may be very important, because unlike red algae (BBA and Staghorn), cyanobacteria may be possibly killed with antibiotics from Petsmart. Several years ago I had to throw away a 7-years-old tank, with filter and everything (just saved the fish) that was infested with what I thought was BBA. May be it was not BBA? Twice in my life I got very bad standard slimy cyanobacteria films that were gone in a week killed with erythromycin. These "new" strands may be resistant to erythromycin, but it is worth trial!

Both the half-leaf-one and this filamentous cyanobacteria have no smell we grew to associate with blue-green slimy films, they do not "crumbles easily to dust" in my fingers (a try that Gerald suggested), instead they prefer to roll in a tight ball. I could not find any branching for the first one. This one sometimes has two types of cells in some filaments, and pseudo-branching (VERY rarely) in filaments with cells type 1. From the attached files you can see:
1. General view on a PLASTIC plant.
2. Two types of cells in the same filament and pseudo-branching of cells type 1
3. Close-up of pseudo-branching of cells type 1
4. Close-up of cells type 1
5. Close-up of cells type 2 with a unique "bend" found very rarely


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In the same store where I found this new Beard-type-cyanobacteria, there was standard BBA (Audeuinella, Rhodophyta) also on a PLASTIC plant (strongly attached). Below are photos to compare the two.


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