5 Steps To Remove String Algae In Aquarium (& What Causes It)

Last Updated on 2023-11-01

String algae is a type of plant with long, stringy filaments. It is most often found hanging from rocks or covering the water’s surface. String algae can quickly get bigger and longer, so it’s best to get rid of it as soon as you can. Before you can control string algae, you must identify it.

In this article, we’re going to tackle the different types of string algae, what they algae look like, and how to get rid of them. We’ll also answer some of the most common questions about string algae in aquariums. So keep on reading!

Table of Contents

Key Takeaways:

  • String algae in aquariums come in various colors and textures, often found on surfaces like glass, rocks, and plants. Its excessive growth can affect the aquarium’s aesthetics, decrease oxygen levels, and potentially harm aquatic life.
  • String algae issues are often linked to poor water quality due to nutrient excess (phosphate and nitrogen).
  • Control methods involve manual removal, water changes, and maintaining optimal water parameters.
  • Introducing algae-eating organisms such as Siamese algae eaters, nerite snails, shrimp, and specific fish species can help manage string algae.
  • Prevention strategies include using algae eaters, regulating fish feeding, controlling lighting, avoiding phosphate-based products, and adhering to a regular water change schedule.

What Does String Algae Look Like?

Too much string algae can make your aquarium look bad, use up oxygen, and possibly hurt the fish and other aquatic life in it. If the water in a tank has changed color, it may mean that the water quality is bad, but green water does not always mean it is unhealthy.

Always check the parameters of the water to see how far it has gone through the cycle and choose the right solution. But before everything else, what does string algae look like?

1. Color

String algae most commonly look green but can also be blue-green, brown, or red. It can be hard to tell the difference between string algae and other plant life, but string algae usually have a slimy or cotton-like texture.

2. Length

 String algae can grow to be several feet long but are typically only a few inches in length. If the algae are left unchecked, they can quickly take over the entire tank.

3. Location

 String algae typically grow on glass, rocks, or plants in an aquarium. They can also be found floating in the water.

4. Amount

String algae can vary in amount, from a few strands to a large mass covering the entire aquarium. A small amount of string algae is not necessarily a bad thing, but too much can be detrimental to the health of the tank.

5. Texture

 As mentioned before, string algae have a slimy or cotton-like texture. This can make them difficult to remove from surfaces.

The close up of aquarium tank full of fish

Is String Algae Bad For Fish?

String algae is a type of filamentous algae that grows on plants, hangs from rocks in waterfalls, or floats on the water’s surface (which is referred to as Blanket String Algae). When the long strands get tangled up, they make thick mats that can double in weight in 24 hours! This ugly green mess sticks to everything it touches and smothers plant life and animals.

Even though it looks alarming, string algae are not that bad for your fish. However, blanket string algae can be a nuisance in freshwater aquariums, as it can quickly cover the entire surface of the water. This type of algae is commonly caused by an excess of nutrients, such as phosphate and nitrogen, in the water. Blanket string algae can also be a sign of poor water quality.

To control blanket algae, it is important to first identify the cause. If too many nutrients are present in the water, steps should be taken to reduce the amount of waste produced by the fish and other animals in the aquarium. This may include changing the food you feed your fish or adding more plants to the aquarium. Water changes can also help to reduce the nutrient levels in the water.

Taking preventive steps, like limiting the flow of nutrients into the lake, could help make nuisance conditions less bad. Before using an algicide on a problem that is already there, it may help to break up large surface mats.

Now, check out this video by Fish For Thought on how you can get rid of string algae!

What Eats String Algae?

String algae are one of the things most algae eaters don’t like to touch. (Common plecos, like bristlenose plecos, won’t care about the stuff.) But luckily, there is an army of hungry creatures ready to eat the string algae in your tank. No matter how big or small your aquarium is or how the water is, something on this list below will work for you.

Siamese Algae EaterEats green algae, string algae, and black beard algae. Consumption decreases as they age.
Nerite SnailKnown to consume string algae. Common, easy to care for, but often available in limited varieties.
Crystal Red ShrimpFeeds on string algae. Recognized for their attractive red and white appearance.
Red Cherry ShrimpPopular type of shrimp as pets, effective at consuming string algae. Requires acclimatization.
Rosy BarbsCan be trained to consume string algae if feed is limited. More effective in non-planted, larger tanks.
Amano ShrimpKnown for effectively consuming string algae when not overfed. Affordable and easy to care for.
Honey GouramiA peaceful fish that can eat string algae. It’s non-aggressive and assists in controlling algae growth.

1. Siamese Algae Eater

The Siamese algae eater is a great addition to most 30-gallon or larger tanks. They will also eat green algae, string algae, and black beard algae. The only thing about these algae eaters is that as they age, they get lazier. When they were small, they ate algae like crazy, but when they got bigger, they would just nibble at it.

(Siamese algae eaters are great fish for any tank! Click the link to find out how to care from them from start to finish.)

2. Nerite Snail

One of the few snails known to eat string algae is the nerite snail. They are easy to find and don’t cost much. Also, they are easy to take care of. However, most of the ones that are available are ugly mud-brown ones.

3. Crystal Red Shrimp

Crystal red shrimp are beautiful red and white shrimp that look great in any tank with the right water conditions. A bonus is that they also eat string algae. Crystal Red Shrimp are just a different kind of bee shrimp, so any other kind should work just as well.

4. Red Cherry Shrimp

Cherry shrimp may be one of the most popular types of shrimp kept as pets. This shrimp can live in a lot of different places and would happily feed on string algae. Make sure you get them used to your aquarium before putting them in, and you shouldn’t have any problems.

5. Rosy Barbs

If you have a bigger tank that isn’t planted, rosy barbs may be the hidden gem on this list for your tank. You can teach them to eat string algae if you limit what they can eat. Once you do, they will get rid of any string algae in your tank for sure.

6. Amano Shrimp

When it comes to getting rid of string algae, the Amano shrimp may be the most well-known freshwater animal. As long as you don’t give them too much other food, they’ll be happy to eat string algae. They’re cheap and easy to take care of, so you should put them high on your list of things to try if you have string algae.

7. Honey Gourami

Honey gourami is peaceful fish that can both be the center of attention and eat algae. Honey gourami can eat string algae with no problem. They are also calm and attractive, unlike some other gourami. They won’t kill the algae in your aquarium, so don’t worry. They are more algae eaters, so as long as you do your part, they will help keep algae from getting out of hand.

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What Causes Hair Algae?

The causes contributing to the growth of string algae are as follows:

1. Excess Nutrients: Accumulation of nutrients like phosphate and nitrogen acts as a catalyst for string algae proliferation.

2. Poor Water Quality: Fluctuating water conditions, such as high pH levels, CO2 deficiency, or irregular lighting, foster an environment suitable for string algae development.

3. Inadequate Filtration: Lack of efficient filtration systems or insufficient water flow in the aquarium can lead to nutrient accumulation, facilitating algae growth.

4. Lighting: Extended periods of excessive light, whether natural or artificial, can stimulate algae growth in the aquarium.

5. Substrate and Surfaces: Organic waste and debris collecting on the aquarium substrate, decorations, or surfaces create an ideal environment for string algae to develop.

6. Overfeeding and Waste: Overfeeding the fish leads to excess waste and uneaten food, decomposing and contributing to increased nutrient levels, further promoting string algae growth.

What Is Black String Algae?

Beards are more attractive on your face than in your aquarium. In an aquarium, it just looks like a fuzzy mess. Even though black beard algae is usually found in saltwater, there are some types that live in freshwater tanks. In fact, aquarist says that these bearded menaces are seen in more freshwater tanks than in saltwater tanks.

Even though its name and appearance suggest otherwise, black beard algae is actually a type of red algae. If you’ve ever killed black beard algae before, you already know that it turns red when it dies. But when black beard algae are healthy, they can be any color from dark green to brownish gray to deep black. Even though its color changes, its look is always the same. 

Like a beard, this algae starts out as small spots of fuzz that stick to the surface of anything in your aquarium.

With time, the black beard algae look more like it has grown for three days. But if you don’t take care of it, it quickly turns into a beautiful, thick, brushy hair jungle; Seriously, it looks like hair from a shampoo commercial. Black beard algae get their food from the water, like most other kinds of algae.

Any place can have black beard algae. The best way to find black beard algae is when it grows on plants. It usually starts to grow on the edges of the leaves and then spreads until it covers the whole leaf.

What Is Green String Algae?

String algae are called claudophora spirogyra in the scientific world. They are sometimes called blanket weeds because they look like a blanket floating on top of the water. They have more than one cell and use light to make food.

Most of the time, string algae live in shallow lakes and streams. You can also find them in koi ponds, water gardens, and aquariums. They can live in both fresh and salt water. Most of the time, they stick to rocks, plants, or other things in an aquatic environment. Once they are joined, they get longer and thicker.

They can look like a tangled mess of fibers or have straight, even lines going through them. Even though they are always in our water, we usually don’t notice them until there is an algal bloom. When they bloom and get too big, many tank owners have to do something to get rid of them. An algal bloom can spread quickly and kill other organisms in the water by making them sick or starving them of food or light.

What Is White String Algae?

In an aquarium, white algae can be a pain. Your fish won’t get sick from these common algae, but they grow and spread quickly. These algae look like a slippery web.

They don’t usually grow on glass, but they can grow on driftwood, rocks, or decorations. White algae are easy to get rid of, and if you know what causes them, you can stop them from growing in the future.

There are many things that could cause white algae to grow in your fish tank. The first and most common thing that can lead to an invasion is water that doesn’t move well. When a new tank is set up, this can happen because the water needs time to settle.

The algae could also be spreading because there isn’t enough or good enough filtration. So make sure that your tank has everything it needs to work well and smoothly. This could also be caused by the lighting, which is explained in more detail below in the section on lighting.

But if your tank gets a lot of natural light or has too much light during the day, it can hurt the fish in your tank and make algae grow.

White algae could be caused by other things, and these are the most common ones. But don’t be afraid to talk to a specialist if you find that none of these reasons explain why white algae are taking over. If you can’t stop white algae from growing, you’ll have to get rid of it as soon as you can.

The first thing you need to do to stop this white algae invasion from happening again is to figure out what caused it. This will help you choose the best way to deal with it. White algae bloom happens a lot when setting up a new tank, especially a smaller one.

So you can measure the amount of nutrients and make changes as needed. Then you can do a few water changes, but make sure to take care of your tank’s inhabitants, as even small changes can make them unhappy.

What is Red String Algae?

Cyanobacteria are often called “Red String Algae” or “Cyano,” but it is not a type of algae at all. Rather, they are photosynthetic bacteria that live in our aquariums when they can. It can be found in any aquarium, but it only shows its ugly face when the conditions are right for it to grow quickly. In a healthy and well-balanced tank, beneficial bacteria and other microorganisms beat out cyanobacteria for food and space.

The way people talk about cyanobacteria in aquariums has changed a lot over the years, and aquarium people are always learning new things as they get more experience. Cyano is a common problem for both freshwater and saltwater hobbyists. Most of the time, you’ll see black or blue-green mats of cyanobacteria in tanks with fresh water. When you have to deal with a bad case of algae or another pest, it can be discouraging and make you question how much you care about the tank. 

When cyanobacteria grow out of control, it forms mats that cover corals and live rock and suffocate them. It looks bad and can throw off the balance of bacteria in your tank. This can lead to instability, which makes it harder to fix the problem. It’s the worst thing that can happen to an aquarist. Many of these pests, like Cyanobacteria, can be avoided or at least kept to a level where they are easy to control with a few simple preventative steps.

How To Get Rid Of String Algae In Fish Tank

There are many ways algae can get into your tank. Anything from another aquarium or a natural body of water that you put in your tank could have algae on it. This includes the water that the plants, fish, snails, and other living things in your aquarium come with. Here are 7 things that you can do to get rid of string algae in a fish tank.

1. Manual Removal

The first step in fighting string algae is to get rid of as much as you can by hand. Depending on how much you have in your tank, what kind it is, and whether or not it’s attached and where, this can be hard. If string algae are stuck to your plants, you can pull them out of the tank to make it easier to clean up the mess.

2. Changing Water and Parameters

Most documents about aquariums tell you to change the water. If too many nutrients are building up in your tank, water changes will help. Depending on the water you use, it may also give the tank a few micronutrients

3. Employ Algae Grazers

Good aquarium habits are important for getting rid of string algae, but you may also want to hire a small cleaning crew to help you fight. A number of fish and other animals will eat at least some types of string algae. We’ve found that the Florida flagfish Jordanella floridae, the Ameca splendens, and some mollies work well.

4. Add More Plants and Get Rid of the Dead Ones

Put fast-growing plants that can reproduce in your aquarium to increase the amount of oxygen. Make sure to get rid of the plants that are dying first since they won’t help you fight algae. Choose plants that will grow big, eat a lot of nutrients, and don’t need much care.

5. Feed the Fish Less

One of the most common problems aquarium owners have is that they feed their fish too much, which costs them money. Not only do fish that eat too much give off ammonia and other chemicals that could be dangerous. But if they eat too much, they won’t have room for other things in the fish tank. 

How To Get Rid Of String Algae In Planted Tank

Trying to keep string algae out of a planted tank is something that a lot of aquarium owners can relate to. A plant that grows slowly is also a good place for algae to grow. It will look like the aquarium plant has dark spots on it. There are a few things you can do to get rid of algae on your plants.

Take Off the Affected Leaves

If the string algae are only on a few leaves, you can pull those leaves off and throw them away. The algae won’t die, but it will be gone from your plant.

Don’t Use As Much Fertilizer on Your Plants

If you use too much fertilizer on your plants, it could be making string algae grow. Cut back on the amount of fertilizer you use and see if that helps.

Don’t Put the Aquarium in a Place With Too Much Light

For string algae to grow, they need light. String algae will grow and spread much more if you don’t give your plants more light.

Put Algae Eaters in Your Tank

If you have an algae eater in your aquarium, it will help keep string algae in check. The Siamese Algae Eater and the Nerite Snail are both good choices because they are cheap and common algae eaters.

Treat It With Chemicals.

There are a few different ways to use chemicals to kill string algae. Copper sulfate and algaecides are two of these. Make sure to follow the directions on the package very carefully.

The plants in your aquarium will be grateful if you take the time to get rid of the string algae. With a little work, your plants will be healthy and free of algae.

What Is The Best Algaecide For String Algae?

Algae are the most talked about thing in the aquarium hobby and probably always will be. It is the main reason why many people stop keeping fish as a hobby. But algaecides might be the best way to solve this problem. Algaecides are chemical compounds whose active ingredients kill algae and/or stop it from growing in your tank.

There are a lot of different kinds, shapes, and sizes of algaecides. Below are the best algaecide for string algae:

Aquarium Pharma-algae Control 

Aquarium Pharmaceuticals Algaefix is a revolutionary product made to get rid of many kinds of algae in freshwater aquariums with live fish and plants. This algaecide controls green water algae bloom very well.Aside from this, it also keeps aquariums with fresh water clean and clear.

Blue Life Flux

Blue Life Flux is easy to use and works well. When string algae are present, levels can be easily reached and kept up quickly. To help clean the aquarium, filter socks are recommended. If you have macroalgae or a refugium, do not use it.

Fluval Edge Algae Cleaner

Fluval Edge Algae Cleaner gets rid of phosphate and nitrite in your aquarium, which helps make the water clear from any type of algae, including string algae. The Fluval Edge Algae Cleaner can be used in any type of aquarium and helps cut down on smells and make tank maintenance easier.

 GreenClean Algaecide

GreenClean is a granular algaecide that gets rid of string algae especially well (though it should work for all forms). It breaks down algae cells on contact by using the power of oxidation. In as little as 24 to 48 hours, there will be less algae that can be seen. This treatment for algae doesn’t use harsh chemicals like chlorine, copper, or phosphate.

Cutrine Plus Algaecide

Cutrine Plus is a professional-grade algaecide that kills all kinds of algae and works quickly in just one to two days. Plus, it has chelated copper, which helps keep algae from growing even after it has been applied. If the water hardness is less than 50PPM, it is safe for koi, goldfish, and trout (You can check with a tank water test kit). 

Algaecides work very well to get rid of algae in your tank. But they should be your last resort. Also, be sure to follow the instructions carefully for whichever algaecide you’re planning to use in your fish tank.

What To Do With String Algae In Betta Sorority

String algae can be a big problem in betta sororities. If not dealt with, it can take over the entire tank. Below we will discuss what to do with string algae in betta sorority.

Put Live Plants in Your Fish Tank

Live plants are great at cleaning the water of too many nitrates. String algae grow when there are too many nitrates and other waste products in the aquarium. Having live plants is a great way to naturally stop this from happening. 

Bring In Some Animals That Eat Algae

Adding a cleaning tank mate for your betta sorority that eats string algae can help get rid of it. If you do decide to add a fish that eats algae, make sure your aquarium can handle another fish. We recommend a size of 8 US Gallons (30 liters) or more for a single betta and a small algae eater. 

Cycling, Filtration, and Changes in the Water

A filtered and cycled aquarium is important for anyone who wants to keep fish. Having an aquarium that has been cycled and a good filter is important for preventing string algae because it helps to get rid of ammonia, nitrites, and nitrates quickly. As we said above, string algae eat nitrates, so the more nitrates there are, the more algae there are.

Keep an Eye on Your pH and Nitrates

If the pH level in the aquarium is too high, string algae can grow and spread. Bettas live in soft water, so a pH of 7 or close to it is best. If your pH is on the higher end of the scale, string algae are more likely to grow in your aquarium.

Use a Socket Timer To Make Sure the Lights Don’t Stay On for Too Long

If the aquarium light stays on for too long, string algae can become a problem. At least 8–10 out of 24 hours, the light should be off. To make sure your betta gets the same amount of light every day, you might want to buy a socket timer that can be set to turn the lights on and off at certain times.

Make Sure Your Aquarium Is Not Near a Window or Where It Will Get Direct Sunlight

Most people do keep their aquariums away from windows or in rooms where the light doesn’t hit them directly, but if your aquarium is in a room with several windows, for example, it will get more sunlight. When you set up your aquarium, you should always think about where it will go. Because every day of direct sunlight can make string algae grow faster.

Get a Good Aquarium Vacuum.

String algae that have been cleaned off usually settle somewhere in the aquarium. Sometimes it ends up on the gravel, but more often, it ends up in cracks and crevices (along with other waste). There are a lot of good siphons and vacuums for aquariums on the market.

How To Prevent String Algae

The best way to fight string algae in your tank is to keep it from growing in the first place. Follow these tips to keep algae from getting out of hand.

Add Algae E aters

Algae eaters are a great way to keep algae growth in check. Choose fish that are known to be good algae eaters, such as siamese, nerite snails, or otocinclus catfish. These fish will help to prevent string algae in your fish tank.

Don’t Give Your Fish Too Much Food

If you give your fish too much food, algae can grow. This is because the extra food will go bad and release nutrients that algae need to grow. So, make sure you only give your fish what they can eat in a few minutes.

Make Sure Your Aquarium Has Enough Light

For algae to grow, they need light. So, putting your aquarium in an area with a lot of light can help stop algae from growing. You can also block some of the light with an aquarium cover.

Don’t Use Products With Phosphates in Them

Phosphates can help algae grow. So, it’s best not to put anything in your aquarium that contains phosphate. This includes things like fertilizers with phosphate and food for fish.

Use a Phosphate Remover

If phosphate is already in your aquarium, you can get rid of it with a phosphate remover. This will help stop the growth of algae.

Use an Algaecide

If your aquarium already has algae, you can kill it with an algaecide. Make sure to follow the algaecide’s directions so you don’t hurt your fish.

Change the Water

Changing the water in your aquarium often is one of the best ways to stop algae from growing there. This will get rid of the food algae needs to grow. Make sure you have a regular schedule for taking care of your aquarium.


Do Goldfish Eat String Algae?

Goldfish will eat any algae, including string algae, from anywhere they can find it. However, even though goldfish eat algae, and they will eat a lot of it, you can’t count on them to keep your whole tank clean. If you want your tank to look clean and nice, you may have to remove some algae yourself.

Do Shrimp Eat String Algae?

When it comes to eating string algae, the Amano shrimp is the most effective. These shrimp are always busy grazing on all the surfaces in the tank, and in the process, they cut down on the amount of algae on the decorations.

Do Snails Eat String Algae?

String algae are something snails eat, and they are very happy to do so. Especially the Ramshorn snails, they are great at keeping your tank clean, healthy, and full of life. 

Will Daphnia Eat String Algae?

Daphnia eats almost any kind of algae they can find in their environment. However,  they tend to avoid filamentous algae, which can be bad for their health due to their limited size.

Do Plecos Eat String Algae?

The Common Plecos are known for eating a large number of string algae. To get your pleco to help control your algae problem, it’s important to pay attention to their size and how much you feed them. 

Will Fish Get Caught In String Algae?

The main problem with string algae is that if it grows out of control, it can quickly use up all the oxygen in a pond, killing fish and plants. Fish can also get caught in the string algae, which can kill them.

What Are Some String Algae Eaters?

True Siamese algae eater, Rubber-lipped pleco, Panda Garra, Juvenile Chinese algae eater, and American flagfish are some of the most common string algae eaters. However, to achieve the best algae cleaning result, it’s important to choose the right type of string algae to graze.

What Fish Eats String Algae?

One of the most common algae eaters for ponds is the common pleco. They are renowned for consuming a lot of string algae. It’s crucial to pay attention to the pleco’s size and how much food you feed them if you want them to assist in reducing your algae problem.

Is String Algae Bad For Bettas?

String algae are not harmful to your betta. But if it becomes too much that it’s blocking some nutrients that they need, you need to do something about it. 

Should I Put Hornwort With String Algae In My Aquarium?

String algae in an aquarium can be controlled by hornwort. They compete with algae by eating the same things, helping it reduce its production. Therefore, you can put a Hornwort with string algae in your aquarium.

Do Trapdoor Snails Eat String Algae

Trapdoor snails eat string algae. So, if you often have string algae in your tank, these creatures will love to munch on it.

Does White String Algae Grow On Glass?

White string algae usually don’t grow on glass, but they can on driftwood, rocks, or decorations. White algae are easy to get rid of, and if you know what causes them, you can stop them from growing in the future.

What Is The Best String Algae Removal Tool?

An algae twister is a good way to remove string algae or blanketweed from your pond by hand. Use it to gather string algae mats and strands.

Will UV Light Kill String Algae?

UV lights do not kill string algae. String algae are attached to different parts of your water environment and, therefore, will not flow past the UV light. 

Will Phosphate Remover Kill String Algae?

Only the pO4 is taken out of the water by phosphates removers. It can’t kill the string algae in any way.


String algae grow quickly, so it’s best to get rid of them as soon as possible. They can be a problem in aquariums with fresh water. This ugly green mess sticks to everything it comes in contact with and suffocates plants and animals. Lucky for you, there are a lot of things in your tank that will eat the string algae which we have mentioned above. They can’t clean your tank on their own, though. So, to keep the water clean for your fish and plants, it’s important to choose the right kind of algae to eat and the best methods to clean and keep them from coming.


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