Types of Aquarium Algae (14 Common Varieties)

If you ask an aquarist- what is the most annoying thing you experience with your tank? I am sure around 90 out of 100 will say its aquarium algae. It’s not only irritating but also painful, and some even could be harmful to your fish tank.

If you are keeping aquariums or fish tanks for sometimes now, you know it very well that it’s like a natural process. Aquarium Algae will come; you just have to be prepared with the countermeasures and keep the maintenance at a good level.

You can reduce the possibility of developing different types of aquarium algae in your tank, but can’t obliterate them. Since you are here, either you are facing already one or planning to start a tank for yourself and curious to know the possible upcoming problems.

Sometimes it’s hard to identify which alga is in your aquarium and what it can do and what you can do against them.

So, that’s why we will be answering some common questions: What kind of algae is in my aquarium? How do you identify different types of algae? How do you kill algae in an aquarium?

And some other related things about algae. We tried to accumulate all the common or usual types of aquarium algae in a single article for your convenience.

Well, let’s check which one you may have and how you can fight those algae and keep your aquarium fresh.

There’s a total of 14 types of aquarium algae we have mentioned here, what they look-like or identification, common causes of their appearance, and how you can get rid of them.

Now, Let’s dig into the main part:

1.Blue-Green Algae (BGA)

Blue-green algae are the Cyanobacteria from the bacteria types but usually mentioned as Blue-Green Algae, though they aren’t. This bacteria or blue-green algae is often seen in water bodies and very common in Minnesota, USA. Cyanobacteria thrive in nutrient-rich, warm water.

Blue-green algae can “blooms” very fast if the conditions are met (in a Pond or Lake). Some particular types of blue-green algae can cause illness to humans and animals because of toxins generated from them.

Cyanobacteria can photosynthesize like plants. They can use up all the nitrogen of the aquarium’s water. BGA is one of the most common types of aquarium algae.

What do Blue-green algae look like?

Blue-green Algae (BGA) or Cyanobacteria clump together and look like a greenish bundle or green flakes. But they can turn into a brown slimy mat, or reddish-purple and has an earthy/ foul smell.

You can find BGA (Blue-Green Algae) substrate in front of the aquarium, where the light hits most.

Types of Blue-green Algae (BGA):

There’re different types of BGA, some forms gelatinous lumps on dank place, some floats in the water. However, dark green, blue-green, or almost black are common in aquariums.

What causes cyanobacteria/ Blue-green Algae in aquarium?

  • In a planted aquarium, a nutrient disparity can cause Cyanobacteria or BGA outbreak. The increase of Phosphate level also can be a reason.
  • Having lesser nitrate or nitrogen in your aquarium may bring BGA.
  • Changing the water less frequently can be another cause.
  • Exposed to too much light for a long time may allow BGA to thrive.
  • Without the required light for the plants can result in Blue-green Algae spreading.
  • A high level of organic waste also causes BGA to appear.

How to get rid of cyanobacteria/BGA in planted tank/Aquarium?

  • Mechanically removing the Cyanobacteria or Blue-green algae and reducing the nutrients level in the water is a way to get rid of them.
  • Frequent water changes (At least 20 Percent) and turning off the lights for a few days in the aquarium.
  • Reducing the light is a way to fight BGA.
  • Keep your tank clean.
  • Use 200 mg erythromycin for every 10 gallons.
  • Having a potassium level 20 ppm in your tank.
  • Using air stone or removing them can help to get rid of BGA.
  • Fast-growing plants can reduce the BGA growth in your aquarium.
  • Manually remove the Cyanobacteria from the tank.
  • Better water circulation will reduce the BGA appearance.

2.Black Beard Algae (Audouinella /Black Brush Algae/BBA)

 Black Algae or Black Beard Algae is a part of red type algae that plagues both saltwater and freshwater. Also known as red brush algae because of red light phycoerythrin protein production; that gives the algae dark/black purple appearance, and it’s slippery, furry, and soft when you touch it.

BBA also looks like a brush or beard. BBA doesn’t have natural red color, even it’s from the red algae family, like staghorn algae. However, if you use alcohol on this alga, it will become reddish. So, it’s the easiest way to identify whether you’re dealing with a red alga or not.

Beard alga in aquarium cling to the ground tenaciously as it grows, they grow on the leaf of aquatic plants, grains substance, and even on the aquarium decoration.

Causes of Black Beard Algae

  • BBA can be found in densely planted aquascapes and fish tanks. A tank with high fish stock and no plants to densely planted can be plagued by them. Because of high organic water pollution in the tank from the few water changes and overfeeding.
  • Unstable or low carbon dioxide (CO2) can cause the appearance of Black Beard Algae in your aquarium or fish tank.
  • Too much light can cause BBA to bloom in your aquarium.
  • Also, BBA can appear from an imbalance of micronutrients.

How to get rid of Black Beard Algae/BBA?

  • Removing Manually Black Beard Algae from your aquarium or fish tank can be a painful task. If it’s attached to your equipment or glass, use good old-fashioned elbow grease to remove them.
  • Try an algae scraper to reduce the BBA in your fish tank.
  • If it becomes more tenacious, increase the Carbon Dioxide by applying Seachem Flourish Excel, or liquid carbon can be effective.
  • Besides, you can use hydrogen peroxide (H2O2) 3% around 3 minutes on the suspected area and wash the area thoroughly.
  • Regulating the amount of Phosphate production in your tank by removing dead plants, dead fish/shrimp/snails, stop overfeeding and changing the water frequently.
  • Bring some Black Beard Algae eater in your tank, like Amano Shrimp, Siamese Algae Eater, Florida Flagship, etc.

3.Green Dust Algae (GDA) 

Some common names are given by the aquarists to different types of green algae coats, such as– glass algae, dust algae, and spot algae. But as you may know, by having an aquarium in your home that green dust alga is most common and talked about.

Green Dust Algae is like a layer of some loose green dust and slimy, most commonly appeared on the aquarium glass and equipment. GDA can be removed by just using a finger or by giving water flow. Aquarists around the world also know this alga as “green glass pest,” which is very hard to remove from the tank.

If you don’t remove correctly, they reappear in your tank in a very short time where the light source is high. GDA tends to bond on the surface level loosely and can move into the water. It’s one of the most common types of aquarium algae.

Common Causes of Green Dust Algae (GDA):

  • The two leading causes of GDA appearance in your tank are radical changes in light or equipment and alteration of nutrients.
  • Reveal your tank into more light will cause the appearance of GDA.
  • Nitrogen tip can also cause from urea or nitrate can cause green dust algae infestation.
  • Changing the water less frequently.
  • Imbalance in nutrient supply (Mainly CO2) can cause algae appearance.
  • Lack of dominant plants.

How to Get Rid of Green Dust Algae?

  • First of all, wait for 3-4 weeks to let the green dust algae to complete the life cycle. If you do, before completing the life cycle, it will release spores and start another life cycle.
  • After around 4 weeks, change the water and reduce the water level. Afterward, remove them manually.

Alternatively, you can apply these to get rid of GDA:

  • Increase the dominant plant mass in your tank (planted+70%).
  • Optimize the Carbon (CO2) level of your tank.
  • Move your tank into a low light area to reduce light source (4-5 days blackout for extreme case).
  • Changing the light after cleaning may help you to fight green dust algae.

Green Dust Algae Eater:

  • Suckermouth/Bristlenose Plecs
  • Snails

4.Green spot algae (GSA)

Flat, green, tiny spots algae are known as green spot algae (GSA) to the aquarist around the world. GSA attached very strongly on the substrate. Primarily they look like tiny spots like dots of polka. Gradually, with a favorable environment, the tiny spots widen.

Aquarium glass, plant leaves, and decoration are commonplace to find green spot algae. Particularly hardy leaves, long-lived kinds Anubias species. Highly lit tanks are more likely to found this type of algae.

Sometimes it’s hard to identify whether you are having green spot algae or other green algae. Other green algae don’t pronounce spots on your aquarium at the preliminary stage, and spot algae are hard to remove from no matter where it shows up.

Common Causes of Green Spot Algae

  • Imbalance in the nutrients is one of the common causes of green spot algae in a new aquarium.
  • Lack of water changes, depletion, or high (around 3 mg/l or above) phosphate content, and inadequate fertilization can spark the GSA to appear in your aquarium.
  • Like other types of green algae, low water circulation, carbon level decrease, or having your aquarium under the light for a long time also can be the reason.
  • Maintaining your phosphate content can help you to keep track of green spot algae.

How do you get rid of green spot algae?

  • There is no better option than wiping out algae manually from the aquarium glass.
  • Use something with a little sharp edge to obliterate the algae.
  • Use water changes after cleaning the spot algae
  • Check your water phosphate level if it’s a too low dose with some items which will help to improve the phosphate level.
  • You can also use an algae scraper to remove the green spot algae from your aquarium.

Green Spot Algae Eaters:

  • The Zebra Nerite Snails
  • Sun Snails

5.Green Aquarium Water Algae

Microscopical green algae that cause the water to turn green; this is known as green water algae. After a few days, they block the visibility under the water. They are part of the Scenedesmus, Ankistrodesmus, and Chlorella group of algae.

Whitish decoloration of the water causes the water to turn into green. Green water algae freely float in the water. But they don’t settle on other things like glass or plants of your aquarium. It can frighten the aquarist, which will turn the water into pea-soup green like.

However, green water algae are not toxic to the fish. Their appearance can be a reason from a unicellular algae bloom, which gathers energy from the photosynthesis process. This type of algae replicates fast.

Common Causes of Green Water Algae

  • An increase in lighting and nutrients can cause green water aquarium algae to bloom.
  • The rise of ammonia in the water helps these types of algae to appear.
  • Overfeeding your fish also can cause the green water algae (which is because of excess nutrition).
  • Having fewer nitrites required to consume the ammonia can increase the chance of green water.
  • A sudden increase in temperature also sparks these algae presence.
  • The carbon and macronutrient imbalance causes green water too.
  • Improper fertilizer dosing.

How do I get rid of green water algae?

  • Water changes may help a little but won’t effective that much because of its single-celled organism.
  • Using an Ultra-violet Sterilizer one of the best ways to prevent this alga from your tank.
  • Eliminating light will also help you to get rid of green water algae.
  • Using a Diatom filter.

Green Water Algae Eater

  • Snails
  • Shrimp

6.Staghorn algae (Compsopogon sp.)

Staghorn Algae is part of the red algae like black beard algae. Though they don’t look red, if you use alcohol on them, these algae will turn into red. Staghorn is easy to identify and diagnose because they look like the horns of a stag while growing (Hence the Name).

Originally, they look greyish or shades of grey. Almost wire-like or little hairy with a dark color is common.

Staghorn algae can be found on the technical equipment, leaves of the aquatic plants, and aquarium decoration. Removing them manually is a difficult task. Staghorn algae cling onto their substrate firmly.

Also, algae eater fishes or snails seem to don’t like Staghorn that much.

Common Causes of Staghorn Algae

  • Having low CO2 or Carbon in the water.
  • Poor water circulation.
  • Nutrient imbalance from low maintenance or overfeeding can cause Staghorn Algae in your tank.
  • Overdosing of liquid iron fertilizer in a planted tank can increase iron supply more than 0.05 to 0.1 mg/l, this will lead to Staghorn to appear.
  • Too much light also boosts the staghorn algae

How to Get Rid of Staghorn Algae?

  • Using a toothbrush for manual removal can be helpful.
  • Applying bleach can improve the situation; use 1:20 on the affected items for around 3 minutes.
  • Increase CO2 levels and adequate water circulation
  • Using flourish excel can kill staghorn algae, also improve plant growth.

Staghorn Algae Eaters

 Most of the Algae eaters don’t like eating Staghorn. They may eat it but don’t prefer them much.

7.Brown algae (Diatoms)

Bacillariophyceae is al known as Brown Algae. It’s a form of diatom and able to collect nutrients through chemicals (Prosperous, nitrates, and silicate) and photosynthesis, which means they can survive at low light conditions with those chemical supplies available.

It can be found in marine and freshwater tanks. Brown Diatom Algae start as dust on the substrate in the aquarium. After around 5-7 days later, turn into a slimy film, which will cover your plants, substrate, and tank’s glass. Diatoms aren’t great to watch.

It’s kinda stubborn and one of the ugliest aquarium algae types. Brown alga is a colony of diatoms spread when there will be an excessive amount of required chemicals available in the tank. They form a brown coat on your tank’s glass.

Common Causes of Brown Diatom Algae

  • Sometimes it’s common to see brown algae in your tank during the cycling phase, and there is no need to panic or applying countermeasures. In a few weeks of your new tank, diatoms will crowd out by green algae and won’t appear again.
  • Brown Algae or diatoms need silicate for their growth, more specifically, silicon dioxide. Because they create a box-like shape from silicate, using tap water with high silicon dioxide can provide enough material to reproduce in your new tank.
  • Even if your tank has less presence of any other algae, it can boost the reproduction of diatoms.
  • Low light and high levels of nitrates or phosphorus also cause Brown algae in the tank.

How to get rid of Brown Algae?

  • Bereaved from the source of the nutrients is the best way to fight any type of algae.
  • Manual removing the diatoms from your tank is always an open option for you.
  • Increase the oxygen level in your tank by using a filter or changing water more frequently.
  • Deprived from the sunlight.
  • Try to keep the temperature at some normal or low. Warmer water can stimulate algae growth.

Brown Algae (Diatoms) Eaters:

  • Yellow Tangs
  • Otocinclus Catfish
  • Plecostomus

8.Fuzz Algae (Green Fuzz Algae) 

Just like its name suggests, it has a green fuzzy appearance grow as individual filaments on your decorations, plants, and even on your tank’s glass.

Fuzz algae are short green algae. You can be confused with hair algae and fuzz algae. However, hair algae have a dense coat on objects and don’t grow as individual filaments.

Though, among the aquarium hobbyists around the world, think or get confused about whether the green fuzz algae are just early stages of hair algae species.

Common Causes of Fuzz Algae

  • Nutrients imbalance in a new tank is often inhabited by fuzz algae.
  • Low CO2 and high light exposure can cause fuzz algae.
  • It’s also an evident indication of a new ecological system, in between 4-8 weeks of a new setup.
  • In an older setup, the appearance of fuzz algae may cause by macronutrient imbalance.
  • However, having a small population is normal, and there has nothing to worry about.

How To Get Rid Of Fuzz Algae

  • Test your aquarium water’s nutrients level and carbon dioxide levels, then make the required adjustment.
  • Giving a better environment for the aquarium plants can help fight the fuzz algae in your tank.
  • Using Algivorous aquatic animals (Algae Eaters).

Fuzz Algae Eaters

  • Siamese Algae Eaters
  • Otocinclus
  • Bristlenose Plecos
  • Black Mollie
  • Amano Shrimp

9.Hair Algae

Hair Algae are part of green algae. They are quite a common type of algae in the aquarium or fish tank. Hair algae form coats from which heavily stuffed small filaments thrive. A carpet like layers will grow and cover your decoration and plants.

Hair algae are in green color and just look like hair under the water. They’re one of the most common types of aquarium algae.

Aquarists call it hair algae because it’s fell like wet hair when you take out from the tank.

Hair algae are fast-growing and difficult to remove thoroughly.

Common Causes of Hair Algae 

  • During the Immature biological system (which is a new or cycling phase of a tank), hair algae appear in your aquarium, like other green algae.
  • The nutrient disparity also can cause hair algae to appear in your tank.
  • Too much light to your tank also can spark the hair algae to bloom.
  • Having a small amount of healthy and fast-growing aquarium plants can cause too.
  • Lack of nitrogen, which will hold the plant growth, can make the hair algae growing easy and supportive.

How To Get Rid Of Hair Algae

  • Having fast-growing plants and providing enough nutrition to those plants can help outgrow them.
  • Using Algae eaters in the tank.
  • Provide a balanced supply of nutrients.
  • Applying liquid fertilizers with macronutrients support.
  • During the cycling stage, it’s normal to have hair algae. But eventually, it goes out.
  • Apply fogging on the affected area.
  • Blackouts in a severe condition will help you to get rid of them.
  • Using UVC can prevent the growth of hair algae

Hair Algae Eaters

  • Shrimp
  • Snail
  • Florida Flagfish
  • Butterfly Splitfin
  • American Flagfish
  • Mollie

10.Green Thread Algae

Thread algae are species of filamentous algae that form as long green thread and feel loose and soft when you touch them.

Natural algivorous love green thread algae. They belong to different algae species. Thread algae don’t attach on holdfast equipment or organs, or substrate. But form a bushy bed.

Green thread algae’s individual filaments float with the water current and get attached to other decoration and plants. This is how they spread in your aquarium.

Common Causes of Green Thread Algae

  • During the cycling process of your aquarium, green thread algae can appear in your tank because your tank’s microbiology is still immature.
  • As a few days past, the tank’s ecological balance will improve and will reduce the probability of thread algae.
  • Having fewer high growth plants in your tank can aid in the algae appearance.
  • Without proper carbon and liquid fertilizer supply to the plants, they could be outgrown by the algae.
  • Exposing to too much light can be the origin of thread algae.
  • The absence of enough nitrate (less than 10-25 mg/l) will holdup the plant’s growth. Ultimately, your plants will be outrun by the thread or other green algae.

How to Get Rid Of Thread Algae

  • Keep some algivores in your aquarium. They will eat those thread algae.
  • Use more plants that have a high growth rate.
  • If filamentous algae exist only a few places, quickly winding up with a rough surface spindle.
  • If the algae are reappearing in the same place, use fogging with algicides.
  • However, if partly treatment doesn’t work, give algicides treatment to the whole tank.

Green Thread Algae Eaters

  • Amano Shrimp
  • Snails
  • And other common algivorous fish

11.Blanket Weed (Cladophora Sp.)

Cladophora is also known as Blanket weed or Branching Algae.  They still need to be identified. Cladophora sp. Not yet a familiar name to the aquarists. They are arguably the most stubborn among the other known algae.

Consists of rigid, short green filaments that have parts in multiple spots. Because of their growth manner, you can easily identify the blanket weed. It also has a mushroom-like smell.

The cell wall of branching algae is somewhat tougher than other common algae. Algivorous don’t like Cladophora much. It forms a thick clump staying on aquatic plant’s branches or earth covering mosses/plants.

It’ll give nasty smells in case you crush or rub it.

Common Causes of Blanket Weed

  • Unhealthy plants can introduce blanket weed algae.
  • Excess nitrates, light, and carbon dioxide boost growth.
  • A healthy water environment for your plants also helps blanket weed.
  • It even can introduce from plants of private aquaria. Nutrition imbalance can cause a massive growth of blanket weed.

How to Get Rid of Blanket Weed (Cladophora sp.)

  • Changing the nutrients parameters don’t have that much effect on the blanket weed. As we already said that, it’s hard to get rid of it.
  • Pluck it off continuously and thoroughly from the tank, if you have a low infestation.
  • Turn off current while removing them from your tank.
  • Also, you can apply a fogging method to light attack.
  • Restart your tank may be the best thing to do if you have a serious attack.

12.Oedogonium Algae

Oedogonium is part of the filamentous of green algae. It’s a freshwater alga and remains free-floating or affix to the plants of your aquarium. Usually unbranched and has a single cell.

Common Causes of Oedogonium Algae

  • Nutrition imbalance in your tank.
  • Low carbon dioxide.

How To Get Rid Of Oedogonium Algae

  • Check the nutrition level and carbon dioxide level in the tank. Then adjust the level accordingly.
  • If has high, reduce the source and for lower situations, and provide the required balance.

Oedogonium Algae Eaters

  • Rosy Barbs
  • Mollies
  • Amano Shrimp

13.Rhizoclonium Algae

Rhizoclonium Algae is part of the green algae and specifically from the Cladophoraceae family. Like hair algae, Rhizoclonium algae consists of excellent brownish or green stands. When you touch them, they feel like slimy and soft.

Rhizoclonium often grows intertwined with other common algae in your tank.

Common Causes of Rhizoclonium Algae

  • Low maintenance and nutrients can cause this alga to appear in your aquarium.
  • Additionally, low water circulation and CO2 also part of the Rhizoclonium presence.

How To Get Rid Of Rhizoclonium Algae

  • Giving a fine cleaning to the aquarium.
  • Adjusting to the standard nutrition level.
  • Increase the Carbon Dioxide Levels in the tank.
  • Using excel can help to remove them.

Rhizoclonium Algae Eaters

  • Amano Shrimp

14.Spirogyra (Water Silk)

Spirogyra algae is another filamentous green alga. They are slippery and can prevail in your whole tank.

Spirogyra is quick forming and looks like excellent bright green strands.

Because of the arrangement of chloroplasts in a helical shape, Spirogyra got its name as Spirogyra Algae.

Common Causes Of Spirogyra 

  • Spirogyra can appear in a controlled environment. Therefore, identifying the exact cause is difficult.
  • Dead fish, overfeeding, few water changes can cause an ammonia spike, leading to the Spirogyra algae presence.
  • Messy filters and few water changes also can spark as a cause.
  • Concentrating on micronutrients too much and lighting imbalance can help the Spirogyra to grow.

How To Get Rid Of Spirogyra

  • Manually removing them from your tank is always recommended.
  • 3-4-day blackout with cutting off the CO2 source can help.
  • Changing water more frequently is suitable for any algae.
  • Washing your plants and decoration thoroughly.
  • Replacing the low-quality plants with higher ones.

For more details: Read this thread- Spirogyra Treatment

Spirogyra Algae Eaters

  • Rosy Barbs


Final Words

There’re many types of aquarium algae can be seen. We tried to prepare a usual alga you can, or we have faced. So, this isn’t all of the aquarium algae. Typically, you won’t see any other type of algae in your fish tank.

Some algae are harmful to your fish when others aren’t. So, please keep track of your tank, which types of aquarium algae hit it, and try to follow the guidelines given above. It’s also best to communicate with a professional in a serious situation.

He or she can help you by observing your tank’s situation and providing the solution for it. Our suggestion could fail for different reasons like- water condition, your area temperature, and others. Hence, justify your algae type and apply the countermeasures accordingly.

Keep your aquarium clean and safe.

This will be all for today. See you again with different topics and information for your joyful aquarium life. Until then, stay safe and blessed!!

(It’s always a pleasure to have a response from you. So, please let us know your thoughts on our writing and what you have on your mind)

Share with us:

What type of aquarium algae you’re facing right now? Or which one is the worst aquarium algae, in your opinion?



  1. Nice article. Few images would be great.

    • Thanks for the compliment, and I will try to add a few more images.

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