The Most Common Types of Aquarium Algae

Indoor aquariums or fish tanks are just the best. These glass tanks allow you to bring some of nature’s most beautiful animal species inside your home so you can display them in a gorgeous ecosystem filled with interesting aquarium accessories.

But keeping aquariums clean and algae-free can be quite a challenge. You will also note that algae grows and spreads more rapidly during the warmer seasons compared to cold ones.

But what causes algae in your tank and is there a way to treat and get rid of this type of growth for good? In this guide, we reveal the most common types of aquarium algae and offer some advice on how to treat and solve these issues. 

Is Algae Bad for Your Fish Tank?

Most people believe that algae in fish tanks are a bad thing. But this type of growth isn’t as evil as you might think. 

As with plants, algae contain chlorophyll and use a process called photosynthesis to convert light and some organic matter found in water into new algae growth. In the daytime, algae produce a lot of oxygen and at night, they consume some of the oxygen that was produced during the day. 

This type of growth can be good for your fish tank’s ecosystem because many fish species feed on algae and this growth assists with filtrating the water since it feeds on fish waste and other organic matter. Some algae species can also look very charming in a fish tank and can create a more natural look for your tank. 

But too many algae can diminish your tank’s visibility, some varients can turn the aquarium water green and some species can cause bad odors.

What Causes Algae in My Fish Tank?

There is a bit of controversy about what exactly causes algae in tanks. Some believe that algae flourish on lots of light and nutrients like fish waste. Others believe that rapid algae growth is triggered by lots of light and ammonia in a tank and that the ammonia is created when plant matter in the tank starts to decompose. 

Algae species also tend to flourish in tanks that have poor water circulation and poor filtration systems. 

How Do I Get Rid of Algae in My Fish Tank?

There is no such thing as a 100% clean and algae-free aquarium. Well-maintained tanks and tanks with advanced filtration systems may look crystal clear but even these tanks do have quite a few microscopic algae spores drifting about. You will never have a tank that is algae-free but you can maintain the algae growth so your ecosystem can flourish while your tank stays nice and clear. 

While looking for a good treatment for algae growth, you should keep your fish and plant species in mind. Algaecide products that are intended for swimming pools or ponds could cause harm to your aquatic animals. 

Aquarium owners believe that finding a good balance with your aquarium ecosystem can naturally combat algae or prevent excessive growth. But in many cases, a bit of extra intervention is required, especially if you are dealing with a algae species. 

Let’s take a closer look at the most common aquarium algae species and some of the best strategies to help eliminate or control these growths. 

Common Types of Aquarium Algae

There are thousands of different algae species found on earth.  The exact number of species is still unknown but researchers believe that there can be anything between 30,000 up to 1 million different species of algae.

As you can imagine, quite a few of these species can grow in freshwater bodies and as such can show up in your aquarium. The only way to accurately identify algae species is by taking a sample and sending it to a lab for testing. Most people do however avoid this procedure because it can be expensive. Instead, we look for identifiable characteristics and then “assume” or “guess” what species we have in our tank by comparing our findings to some of the most common algae species that are normally found in fish tanks. 

Here is a quick look at algae species that most commonly appear or grow inside fish tanks. 

Brown Diatom Algae

Brown Diatom Algae or Bacillariophyta is usually brown but sometimes green in color. These algae species usually look like dust specks or flour-like substances that cover the fish tank walls and other surfaces. With brown algae, you don’t need an algae scraper because these algae are soft to the touch and can easily be rubbed off the surface with a sponge. 

These types of soft algae are a food source for many aquatic animals like catfish, snails, shrimp, and others. 

The soft algae growth usually becomes noticeable after adding new aquatic plants to tanks. The new plants create high levels of phosphate and silicates that the algae feed on to grow.

Brown algae is the easiest to clear out of a tank because the aquatic plants you introduced to your ecosystem will eventually consume the excess nutrients and the growth rate of this algae will decrease. Algae-eating fish species like catfish also love to feed on these growths and will clear them off your fish tank surfaces in no time at all.

Black Beard Algae 

Black beard algae or black bush algae (Audouinella) are some of the most problematic algae species to get in your tank because there are not many aquatic species that eat these growths. 

These types of algae take about 6 – 8 months to establish in your tank and tend to grow in thick, bushy formations and are usually black or grey in color but it can sometimes appear reddish-brown or brown. Black Beard Algae like to grow on driftwood, aquarium decor pieces, aquatic plants, and other surfaces. If left untreated, this type of growth can completely take over your tank.  

There are lots of different things that can cause this form of algae to start growing in your tank and unfortunately, this aquatic species isn’t very easy to kill.

You can try to introduce algae-eating fish species like siamese algae eaters, Florida flatfish, or Amano shrimp to your tank if you want to naturally kill this type of algae. But even these algae-loving fish species are not fond of this strand.

Most people resolve to chemical treatments to kill black beard algae. There are different types of chemical treatments that you can try like the following:

You can try to spray liquid carbon directly on the algae or add a dose to the aquarium water if you have mold growth. Some plants can be sensitive to liquid carbon so you might want to avoid this treatment if you have a lot of aquarium plants.

3% hydrogen peroxide can also be used to treat black algae. Spray this chemical directly on an infested plant. Wait five minutes and rinse off before returning the plant to your aquarium. The algae will turn red or become clear as it starts to die and some fish species might start to eat the algae now that it is weakened. 

It usually takes about 6 weeks of constant treatments to effectively kill and clear black algae from your fish tank. 

Hair Algae

There are quite a few different species of algae that resemble hair when you remove these growths from the tank. Species like hair algae, string algae, and thread alga are pretty common in fish tanks. Hair alga or Bryopsis tends to grow rapidly and they can be challenging to kill and clear from your tank. 

Green hair alga flourishes in water bodies that contain excess nutrients like iron, a lot of light, or tanks with lots of fertilization. They can also sometimes grow in tanks with very little iron nutrients in tanks that don’t get quite as much light. 

To get rid of hair alga, you can try to create a better balance of light and nutrient balances in your tank. Try to decrease the duration of light your tank gets and increase fertilization or decrease iron levels. You can also add algae-eating fish species like Siamese algae eaters, molly fish, and others to clean up the tank quicker or to get rid of large clumps of thread alga.

Green Spot Algae 

Green Spot Algae or coleochaete resemble small hard green spots and they love to cling to your aquarium walls or to grow on slow-growing aquatic plants. These common forms of algae can be pretty tough to clear off a surface because they cling quite strongly.

This species of algae can be triggered by different things but is mostly caused by too much light in or around the tank or by imbalances of phosphate levels. 

To clear green algae from your tank surface, you can grab a glass-safe algae scraper and gently scrape the spots off your glass walls. 

If you prefer a natural treatment then you can try to add Nerite snails to your tank. These snail species are quite fond of green spot algae. With this snail species, you do need to be aware that they tend to lay small white eggs that resemble sesame seeds all over the aquarium floor.

Blue-Green Algae 

Blue-Green Algae isn’t really a form of algae. Instead, it is a bacteria called cyanobacteria that can resemble algae since it also grows in the form of a slimy plant-like formation. You can identify blue-green algae by its distinctive smell.

The exact cause of blue-green algae in aquariums is still unclear but this bacteria is most common in aquariums with poor water circulation, poor filtration, and poor upkeep.

Algae-eating fish species can’t help you with this type of algae because most fish species avoid these growths due to their smell and because it is actually a bacteria. 

To get rid of blue-green algae, you can start by giving your tank a lot more care. A good filtration system and plenty of circulation or air in the tank can already help reduce the appearance of this bacteria. Try to manually remove as much of this algae as possible by changing the water and vacuuming up any green growths you see. You can also treat the trank with an antibiotic. Repeat this cleaning and antibiotic routine until your tank is clear.

Green Water

 Green water that looks like pea soup is a pretty common issue in fish tanks. The green and murky look of the water is caused by phytoplankton and is usually caused by too much lighting, direct sunlight, an excess nutrient level, or a spike in ammonia. 

Green water algae won’t be killed by flushing out the tank because the particles reproduce much too fast. Even if you do flush the water, the green particles will return within a day or two. 

To treat this type of algae, you can try to black out the tank for a week. This method can be tough on aquatic plants but it could be helpful for starving the algae particles. 

UV sterilizer products can also be used to kill the algae particles. But if you do decide to use a chemical product then you should be sure that the bubbler is in good working condition. Sterilizer products will kill the algae particles. When these particles start to decompose, it could deprive fish species of oxygen and result in fish deaths.  

Final Thoughts

We do hope that this guide taught you more about the most common types of aquarium algae and that the advice for treating these species will help you clear up your own aquarium. If you have other questions about algae species, algae-eating fish species, or need more advice on the best ways to treat specific algae types then you should have a look at some of our other guides. On AlgalWeb, we aim to help you find the best and most efficient ways to deal with algae growth.