12 Types Of Aquarium Algae + All Causes & Treatments



Knowing the main types of aquarium algae is an essential skill for all fishkeepers.

Being able to recognize it when it pops up, understand the cause, and quickly begin treatment is what separates the good aquarists from the great ones.

That’s why we’ve put together this comprehensive guide on the key aquarium algae types you need to know. In it, you’ll find all the essential information to maintain a healthy tank, and keep pesky algae at bay.

The Most Common Types Of Aquarium Algae

While there are many variations of algae out there, we wanted to focus on the ones aquarists deal with the most. There’s a good chance that the types you see below will be the only ones you ever encounter!

1. Black Beard Algae

Black Beard Algae is one of the most common types of algae you can find in an aquarium. In fact, it’s the kind we get asked about the most.

It gets its name from the resemblance it has to facial hair especially when it’s growing on the proper surface. It’s notoriously difficult to remove due to how strong it attaches itself to whatever surface it grows on.


If you have an aquarium with CO2 levels that are out of wack, there’s a chance that Black Beard algae might be in your future. While this is typically considered the main cause of Black Beard Algae, there are some others as well.

Lighting that isn’t stable or consistent is also a very common cause of this type of aquarium algae. Even though most aquarists only think of the artificial lighting they’re using for their tank, there are some other possibilities.

For example, if you use certain floating aquarium plants and don’t trim them consistently there might be spikes in the amount of light reaching the rest of your tank.

Getting Rid Of Black Beard Algae

The first method to try when getting rid of this type of algae is to simply scrub it off yourself. There are many tools you can use that will make this easier, but it’s still going to take a bit of work (Black Beard Algae is very tough).

Some aquarists have success taking out the objects that have algae growth on them and rinsing them with a bleach-water mixture. You don’t want to go crazy with this process, simply rinse with this mixture for a few minutes and then clean them off.

It’s smart to perform some water tests to have an accurate understanding of the various nutrients and parameters in the tank. This will help you reduce the likelihood of a bloom occurring in the future.

Our favorite critters that help deal with Black Beard Algae are:

2. Blue-Green Algae

Blue-Green Algae is an interesting one to include on our list because it’s technically cyanobacterium, not algae. Nevertheless, it’s quite common and can be a major pain in your tank.

It smells, it’s thick (and slimy), and it grows fast. While it won’t cause direct harm to the animals in your aquarium, it will make their environment less hospitable (especially if left untreated). 

It gravitates toward the glass and substrate since these are smooth surfaces that receive a lot of light. However, it can often be found on smooth large rocks as well.


This type of algae will grow as a result of the common causes. Too much organic waste in your tank (either from overfeeding or lack of proper cleaning) creates the perfect environment for Blue-Green Algae to thrive.

If your aquarium is getting more light than necessary that will also add fuel to the fire. While it tends to grow more easily in still water, it has been found in tanks with a solid current as well.

Getting Rid Of Blue-Green Algae

The easiest way to start getting rid of Blue-Green Algae is by scrubbing out as much as you can and performing a water test. This will not only address the problem immediately, but it will also give you some valuable information on why it’s growing.


API Algae Scraper and Pad Kit

API Algae Scraper and Pad Kit

  • Contains one API algae scraper
  • Scraper features long and durable build quality
  • For use in glass aquariums only
  • Features easy storage hook for your convenience

A partial water change is also a good idea. The combination of these two should be enough for most moderate causes.

However, if the growth is extensive you’ll need to try some more drastic measures. This involves changing out half the water, adding potassium nitrate (if your nitrates are low), adding an airstone, and blacking out your tank entirely.

When we say “black out”, that’s exactly what we mean. An opaque lid and no lights will mean the Blue-Green Algae has no way to survive. Once this has been done you can do another partial water change and get rid of the airstone you included.

3. Cladophora (aka Blanket Weed)

Cladophora is a type of aquarium algae that’s a pain to get rid of. Out of all the different kinds on this list, Blanket Weed might be the most feisty.

It’s quite stringy and will grow tightly together, making it hard to remove and harmful to the vegetation in your aquarium. It grows in a thick “blanket” and can be found on any number of objects.

It’s quite smelly too!


The most common cause of Cladophora in a tank is when it gets introduced via another plant. If you mistakenly purchase and add a plant to your tank that has Blanket Weed on it (even in very small amounts) there’s a strong chance it will grow in your aquarium as well.

This can usually be avoided by buying healthy plants from reputable sellers. You can never be 100% sure though!

If you have suboptimal water conditions in your tank that can also encourage the growth of Cladophora. However, this type of algae doesn’t require those conditions to grow.

Getting Rid Of Cladophora

The real issue when trying to remove Blanket Weed Algae from your aquarium is the fact that you need to do it manually. This will get extremely tedious since it’s almost impossible to find and remove each strand.

Since this type of aquarium algae is not reliant on nitrates, lighting, or CO2 in order to grow, you don’t have the luxury of beating it with technical prowess. You just need to get in there and start removing it!

A smarter way to work is by attacking visible spots with hydrogen peroxide or even liquid CO2. You’ll likely be playing whack-a-mole with this algae for a while though.

4. Hair Algae

Hair Algae is one of the most common types of aquarium algae on our list. We’d guess that almost every freshwater aquarist out there has dealt with this at one point or another!

Fortunately, Hair Algae isn’t harmful to the creatures in your tank. But that doesn’t mean it’s not a nuisance. 

The long hair-like strands can grow at a rapid pace, primarily targeting any plant life and vegetation you have in the tank. If left untreated it will expand to other surfaces as well.


You’ll usually find that tanks with Hair Algae are low on CO2, get too much light, or both. These conditions are perfect for this type of algae to grow and need to be addressed if you want to remove it from your tank.

Getting Rid Of Hair Algae

If your tank is low on CO2 then the obvious place to start is by adding more to the tank. There are a number of different ways you can do this depending on your setup, so choose the method that’s right for you.

We also recommend taking a look at your lighting situation to see if it can be reduced a bit. Sometimes aquarists use low-quality lights that actually have a higher output than they realize!

It’s also a good idea to try and get rid of some by hand. You can use your hand, tweezers, or any other tool you have handy. The more you can get out the better, but if you’re unable to remove some without injuring your plants you can let the condition changes above do the rest.

Fortunately, there are a handful of critters that go after this type of algae. Including any of the following in your tank should make a big difference:

5. Green Spot Algae

Green Spot Algae is exactly what the name indicates. These small green spots can quickly take over all parts of a tank and create a rather unpleasant look.

While they start as spots, the space between them will get smaller and smaller as the growth becomes more prominent. If left unchecked, this type of algae will end up creating a solid layer on whatever surface it grows on.


There are a number of different reasons for Green Spot Algae growth in a tank. This isn’t a one or two cause algae like some of the other kinds on our list!

A low amount of CO2 and a nutritional count that is out of whack are two of the most common causes. Fortunately, they’re easily fixed once you’re aware of the problem.

Some of the other common causes apply here as well. Too much light, a lack of flow in the water, and infrequent partial water changes can all promote Green Spot Algae growth.

Getting Rid Of Green Spot Algae

Since there are so many different possible causes of Green Spot Algae, it’s important to gather some information first. You don’t want to jump into the process of removal and treatment before you know what the problem is!

Start by doing some water tests to check for any levels that might be concerning. If anything stands out when it comes to nutrients or parameters, address it directly.

From there you can clean up what algae you can and perform some partial water changes to start cleaning things up a bit. You should also look into your lighting situation to see if you should dial things back a bit.

Most aquarium-friendly snails will be helpful with Green Spot Algae.

6. Staghorn Algae

Staghorn Algae has a very distinct look that stands out from all the other kinds on our list. It’s very durable and will grow on any part of your tank (plants, glass, decorations, etc.) without much trouble.

Due to their sturdy build, it can be quite tricky to remove by hand. This type of algae is also quite good at wrapping itself around tough to reach places.


Luckily there are two main causes of Staghorn Algae. The first is insufficient water flow. Still water is far more likely to get this type of algae than moving water. That’s obviously not something you can always address due to the inhabitants of your tank, but it’s worth knowing.

The other common cause is low CO2. As you can probably tell by now, low CO2 levels can increase the chance of various kinds of algae growth in your aquarium. Staghorn is no different.

If you have a buildup of certain nutrients (past their normal level) this can definitely play a part as well. 

Getting Rid Of Staghorn Algae

Since Staghorn Algae is so incredibly strong, trying to remove it by hand is a nightmare. Not only is the process frustrating, but it’s also highly unlikely that you’ll get rid of 100% of the algae.

Instead, you’ll need to work smarter. Test your water and fix any nutrient levels that might be out of control. Performing some partial water tests is also a great way to start reclaiming your tank.

You can also take any objects that have been overtaken with this algae and give them a quick bleach rinse. A brief scrub or dunk into a bleach-water mixture will do a great job of killing off this algae.

7. Spirogyra Algae

Spirogya Algae is a type that many aquarists don’t know much about. That’s not good, because this algae has a very fast rate of growth!

It’s kind of funky-looking and can coat your tank in slimy green strands. It’s just gross and can be a pain to get rid of as well. The consistency also makes it great for clogging up and filtration gear you’re using in the tank.


The most likely cause of Spirogyra is suboptimal water cleanliness and nutrients that aren’t managed properly. This type of algae can be a little bit sneaky because seemingly healthy tanks can suddenly become overrun.

Excess lighting is also another possible cause you’ll want to look into. Like most algae, a bunch of light can encourage rapid growth.

Getting Rid Of Spirogyra Algae

Getting rid of Spirogyra can be pretty difficult, so prepare for a fight! Since it will often grow around vegetation and other hard to remove places, it’s not as simple as scooping it out.

While a lot of aquarists like to try treating it directly with carbon products or hydrogen peroxide, those are a bit inconsistent. Some aquarists have been able to totally remove Spirogyra with these methods, but others haven’t seen any improvement at all.

This is likely impacted by the amount of algae that’s in the tank to begin with. However, no one knows for sure!

You can also try blacking out the tank for 2-3 days to see if that makes an improvement. We like doing a partial water change before giving this a try.

8. Green Dust Algae

Green Dust Algae is another common type that plagues many freshwater tanks. While it can look a bit like Green Spot, the way it grows is quite a bit different.

Instead of this algae having small gaps between it, it will quickly make a solid layer that builds up on a variety of surfaces. The problem is that while it’s fairly easy to scrub away, the process simply breaks off smaller pieces that start to grow all over again. It’s quite persistent!


If you have a fairly new aquarium that hasn’t gone through the proper cycling process, that could be contributing to the growth of this algae. This is a mistake that can happen with beginners, but also experienced aquarists who may have gotten impatient to get their new tank going.

Of course, nutrient imbalance and low CO2 are always worth considering as well. If your tank has these problems it’s far more likely to end up with algae growth.

Getting Rid Of Green Dust Algae

The cool thing about this type of algae is that the removal process is very simple. Instead of a lot of cleaning and fancy treatment options, you simply need to wait things out.

Here’s what we mean:

Instead of trying to actively clean and scrub away Green Dust Algae (which will only help spread it), wait for it to release spores. This will take about 4 weeks from the time the growth first appears.

Once this happens, simply perform a water change and give the tank a good cleaning! If you timed it right there’s a good chance this algae won’t come back. If a bit comes back in the future, repeat the process.

9. Fuzz Algae

Fuzz Algae is quite common and will show up in almost all freshwater tanks at one point or another. This is something that a lot of aquarists don’t actually realize because it can be rather unnoticeable in small amounts.

However, if you let it get out of control this type of aquarium algae will definitely cause some problems. That’s why it’s important to take this seriously and stop any growth before it gets serious.


Fuzz Algae is just like a lot of the other kinds on our list. The main causes are low CO2 and a nutritional imbalance.

Fortunately, these are causes that are fairly easy to fix if you know what you’re doing.

Getting Rid Of Fuzz Algae

Before you rush into any kind of treatment it’s smart to gather some information on the state of your water first. This will allow you to make smart and accurate decisions about how to treat the tank.

From there, all you need to do is address the root cause. If it’s CO2 then follow the plan listed above. If it’s another nutritional issue then go down that road instead.

Many of the best algae eaters will nibble on Fuzz Algae. However, there are a couple that stand out from the pack. They are:

10. Oedogonium Algae

Oedogonium Algae is one of the least common types of algae on our list. As a matter of fact, many aquarists don’t even know it exists!

It can be a little hard to notice at first since it gravitates toward vegetation in your tank. It’s a bit fuzzy or fluffy looking, but you’ll need to keep a close eye out if you want to catch it early.


Oedogonium Algae can arise if the usual suboptimal conditions are met in the tank. Dirty water, low CO2, and a general nutritional imbalance will make it easy for it to grow.

Getting Rid Of Oedogonium Algae

There are plenty of great products you can use to dose and adjust these levels in your tank. Do a water test first to better understand the root problem before you begin though.

Increasing the consistency of partial water changes is also a good idea going forward.

11. Rhizoclonium Algae

Rhizoclonium Algae is often confused with Hair Algae due to the similar consistency and color. However, they are technically different (even though your approach for treatment is very similar).


The main reasons this type of algae grows in freshwater tanks are CO2 levels that are unchecked and poor nutrient balance. However, other factors like stagnant water in the tank and a general lack of cleanliness can also cause Rhizoclonium.

Getting Rid Of Rhizoclonium Algae

We recommend starting with a quick water test to identify any potential issues. Regardless of the results though, a water change and some manual cleaning are a good place to start.


API Algae Scraper and Pad Kit

API Algae Scraper and Pad Kit

  • Contains one API algae scraper
  • Scraper features long and durable build quality
  • For use in glass aquariums only
  • Features easy storage hook for your convenience

From there you can look into addressing any of the other issues that might be causing this algae to grow. This type is a lot easier to attack if you’ve made an impact on the overall quality of the water first.

A lot of other guides recommend Amano Shrimp. They’re definitely helpful, but won’t be enough to completely keep this algae from ever growing in your tank.

12. Green Water

This is a bit of a different situation, but it’s definitely worth including on our list. Instead of there being specific growth patterns, this refers to the general state of an aquarium where the water has become green.

While it might look like someone dumped food coloring in your tank, look closer. This change in color comes from very small particles of algae that are floating all throughout the water. These particles will hardly ever condense on objects in your tank, and instead will float until they are dealt with.


When you look at aquariums that are affected by Green Water, there are a couple things they have in common.

The first is too much lighting. Green Water Algae will thrive and bloom when there’s an abundance of light in the tank.

The second is a rise in nutrients found in the water. There are a number of possibilities here, but they can all lead to rapid growth.

Also, general tank cleanliness and the frequency of partial water changes can play a role as well. This isn’t unique to Green Water, but it’s still a big factor.

Getting Rid Of Green Water

You’ll likely have to do a full blackout of the tank in order to address this. Since light is such an important part of the growth, the lack of it will cause this algae to die.

You should also try a UV sterilizer to take things to the next level. The combination of these two tactics should be enough to rid your tank of Green Water.

Any of the standard algae eaters will do a good job. They’re obviously not a complete cure but can give you a bit of an edge when trying to prevent this growth from occurring in the future.

General Guidelines For Dealing With Algae

As you can tell, there are some common factors that make it possible for these types of aquarium algae to grow. This section will summarize them.

Get Some Help

We’re a big fan of using algae eaters to help keep your tank clean and well-maintained. These little critters will spend every waking moment looking for algae to nibble on!

While they’re obviously not a replacement for filtration and good water maintenance habits, they’ll help a lot more than you think. Just one or two creatures (depending on the tank size of course) can make a noticeable difference.

Don’t Overfeed

Overfeeding your fish is one of the fastest ways to encourage algae growth in your aquarium. The excess food will stick around in the tank, begin to break down, and lead to poor water quality and potential bloom.

The easiest way to avoid this is by carefully learning the care requirements of the species you own. This will give you an idea of how much they need to eat and what kind of feeding schedule you should have them on.

Pay close attention to them during feeding time (especially for the first couple of weeks). If you see that food is being uneaten, adjust the quantity accordingly.

Change The Water Consistently

Performing regular water change is something that is easy to put off. In fact, we consider it one of the most common sins aquarists commit!

But it really makes a big difference. Having a consistent schedule where you perform a partial water change will go a long way in making sure the water stays clean. This will significantly lower the chance of algae bloom in your aquarium.

Keep An Eye On Your Lighting

Excessive lighting is one of the easiest ways to end up with different types of aquarium algae. While it seems like something that’s easy to manage, it’s actually quite deceptive!

You could have a light that’s giving off more output than you realize (a common issue with low-quality products). You could also have a lot of plant life that hides the light until you trim it down. When the trimming happens, this flood of light can bring about new algae.

Now You’re Ready

We hope this guide on the different types of aquarium algae will help you maintain a happy and healthy tank.

As you can see, there are many different kinds of algae that can affect your tank. While this fact can seem intimidating to some aquarists, you shouldn’t worry.

Having a strong understanding of what causes these types of algae and knowing how to get rid of them makes you a more capable owner. Simply remember what you learned in this guide and you’ll be ready for anything!


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