7 Causes Of Green Hair Algae In Fish Tank (& What To Do)

Last Updated on 2023-09-20

Green, slimy, and gross – that’s how most people would describe green hair algae. This type of algae can be a nuisance in freshwater aquariums. If you’ve ever had to deal with hair algae, you know how frustrating it can be. But don’t worry; there are a few things you can do to get rid of this pesky green hair algae for good. In this article, we’ll discuss what hair algae are, what causes them, and how to get rid of them once and for all. We’ll also provide some tips on preventing hair algae from coming back in the future.

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What Is Green Hair Algae?

Green hair algae is a type of algae that can grow on many surfaces, including rocks, plants, and glass. It gets its name from its long, thin, green strands that look like hair. Green hair algae can be aesthetically pleasing and annoying, depending on where it’s growing. In some cases, it can be harmful to plants and animals.

Green hair algae are usually not harmful to humans, but they can be unsightly if it’s growing on something you don’t want. In aquariums, green hair algae can quickly take over and start choking out other plants. It can also be challenging to remove once it’s established.

Once green hair algae have taken hold, the best way to remove it is physically. This means manually removing it from surfaces with a brush or other tool. You can also try using chemicals to kill the algae, but this can be difficult without harming other aquarium plants.

What Causes Green Hair Algae?

Just like other plants, green hair algae need water, light, and food to grow. Algae can grow like weeds in a tank when there are too much of any of these things. Read below to discover what causes green hair algae in your aquarium.

Too Much Light

Algae need light to grow, but if there is too much light, the green hair algae will grow too fast. If you have real plants in your aquarium, they will also need light to grow. But you can turn off the lights for a short time every day to help the green hair algae die back.

Overfeeding Your Fish

Fish waste contains the nutrients that green hair algae need to grow. If you feed your fish too much, it can cause green hair algae to grow. You should only give your fish what they can eat in a few minutes. 

Not Enough Filtration 

Filtration is needed in aquariums to get rid of waste and poisons in the water. However, filters can also eliminate snails and shrimp that eat green hair algae. Green hair algae will have more chances to grow if you don’t have enough filtration.

Aquarium Gets Direct Sunlight 

Green hair algae need sunlight to grow, just like any other plant. If you put your aquarium in a room with a lot of direct sunlight, green hair algae will grow there. You can either move the aquarium to a different spot or put a curtain over the tank to block out the light.

Too Many Fish in the Tank

With more fish comes more waste, which can cause green hair algae to grow in large numbers. You should have the right number of fish for the size of your aquarium. One inch of fish per gallon of water is a good rule of thumb.

pH Imbalance

Aquariums with a pH that is too high or too low often have green hair algae growing in them. If your pH isn’t in this range, you’ll have to change it. A pH test kit can be used to check the pH of your aquarium.

Overdue Water Changes

Aquarium water needs to be changed often to eliminate waste and toxins. If the water isn’t changed often enough, green hair algae can grow in it. As a general rule, you should change 10-15% of the water every week.

A green beautiful planted tropical freshwater aquarium with fishes

How To Get Rid Of Green Hair Algae

Green hair algae grow quickly and can take over your tank in a few days. It makes your plants die, it can trap your fish, and it just looks bad. It’s something nobody wants, but how do you get rid of it? Below are 7 ways how:

1. Manual Removal

Green hair algae are easy to get rid of because it is soft and doesn’t stick to things very well. Use a toothbrush, a small bottle brush, or pipe cleaner and twist the strands on the brush before pulling them up and out of your tank. If the green hair algae are growing on a loose piece of hardscape, like a rock, you can take it out and clean it in a separate water container. 

2. Add More Plants

In a planted aquarium, all the plants and algae are actually competing for the same food and water. Once you know this simple fact, it’s easy to see how healthy plants can be such an excellent tool for fighting green hair algae! Adding more aquatic plants, especially ones with stems that grow quickly, can starve green hair algae and make it die off on its own.

3. Improve Your Water Source

The water is what makes an aquarium. It is the base of the whole system, so it is usually the first place to look when green hair algae problems start. Check to see if your water source has more of the silicates, nitrates, and phosphates that green hair algae eat.

4. Improve Your Water Parameters

To keep the water quality high, it is very important to test it often and change some of it. Some nutrients, like nitrates and phosphates, can cause hair algae to grow in an aquarium that is not well taken care of. But plants and even corals need these nutrients to stay alive, so regular maintenance is the best way to keep the concentrations at a safe level.

5. Use an Algae Eater

Many different types of algae eaters can help control green hair algae in your aquarium. Some, like the Siamese Algae Eater, will only eat certain types of algae. But others, like the Black Molly, will eat just about anything!

6. Use a UV Sterilizer

Using a UV sterilizer is a great way to control green hair algae and many other types of algae in your aquarium. UV light can kill the algae cells, preventing them from reproducing.

7. Use Chemical Treatments

If all else fails, you can always use chemical treatments to get rid of green hair algae. Many different products on the market will kill green hair algae, but you need to be careful not to kill all the algae in your aquarium. Some products will only kill certain types of algae, so make sure you read the labels carefully.

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How To Remove Green Hair Algae From Live Rock

Even though algae are a natural type of plant, you don’t want them in your aquarium. We’ll talk about how to remove green hair algae from live rocks.

Take Rocks Out of the Tank

To clean algae off the rocks in your aquarium, you’ll need to take them out of the tank first. Get each rock out with a small net and put it in a bucket of clean water.

Use an Aquarium Siphon

Then, use an aquarium siphon to remove the algae from the rocks. First, put the siphon tube’s end into the water bucket and turn on the pump. Then move the tube around each rock to get rid of all the algae.

Vacuum the Gravel

Once you’ve cleaned the rocks in your aquarium, you’ll need to vacuum the gravel. This will get rid of any algae that fell off the rocks while they were being cleaned.

Use Bleach

Mix one part bleach with ten parts water in a bucket to make a bleach solution. Then, put the rocks in the bucket and give them 30 minutes to soak. Take the rocks out after 30 minutes and wash them with clean water.

Put the Rocks Back in the Aquarium

Once the rocks are clean, you can put them back in your aquarium. Make sure to run clean water over the rocks before you put them back in the tank.

What Snails Eat Green Hair Algae?

Green hair algae is a type of algae that commonly grows in marine aquariums. Although it is not harmful to most fish or invertebrates, it can be unsightly and difficult to remove once it takes hold. Many aquarists consider green hair algae to be a nuisance algae, and it is often considered one of the most challenging types of algae to control. Luckily, there are snails that you can consider adding to your fish community to help get rid of green hair algae.

Ramshorn Snails

People usually think ramshorn snails are a pest, but you can put them to work eating green hair algae in your aquarium. Like most of the other things on this list, they won’t solve your algae problem on their own, but they can be a good part of a plan to get rid of algae as a whole.

Pond Snails

People often call these little snails “pest snails,” but they are the most hardworking cleaners in the aquarium. They are free, can make more of themselves on their own (if you have one, you will get more), and will eat almost anything, even green hair algae.

Nerite Snail

One of the few snails known to eat green hair algae is the nerite snail. Nerite snails aren’t too hard to take care of, but they do need certain things.

Mystery Apple Snail

Mystery Apple Snails will eat most kinds of algae, including gren hair algae. They spend most of their time on the bottom, where they graze for algae and pick up bits of food that have fallen there.

Malaysian Trumpet Snail

When fully grown, these busy snails that eat green hair algae will only be about 2 centimeters long. However, they are great at keeping your aquarium clean because they will eat any kind of algae and any leftover food or plants.

What Fish Are Good For Eating Green Hair Algae?

Fish that eat green hair algae are herbivores, so it’s likely that they will eat other plant foods in addition to algae. Let’s talk about your choices for fish that eat algae:

Siamese Algae Eater

The Siamese algae eater is one of the best fish at eating algae because it eats many different kinds of algae, including green hair algae. These algae eaters are also great because they will eat some algae that other algae eaters won’t, like black beard algae.

Chinese Algae Eater 

They are not one of the best green hair algae eaters on this list because they tend to get lazy as they get bigger. However, when they are young, they eat different kinds of algae. You should give this species places to hide, like hollow logs or caves in the rocks.

Twig Catfish

The twig catfish is the one on this list of fish that eats green hair algae that needs more special care than the others. They also need places to hide in the tank because they are usually very shy.

Otocinclus Catfish

The otocinclus catfish grows to a maximum of 2 inches and is one of the smallest green hair algae-eaters on this list. This species does well in community tanks and gets along with other bottom-feeders, but they shouldn’t be kept with large or aggressive fish like cichlids.

 Whiptail Catfish 

The whiptail catfish eats everything, so in addition to green hair algae, it will also eat things like fish food that haven’t been eaten. These fish have neutral colors like black and tan, and they can grow up to 6 inches long, so they need a tank that can hold at least 50 gallons.

Bristlenose Plecostomus

This specie is very good at eating green hair algae and fish food that has been left over. Bristlenose plecos get along with most peaceful fish, and they can live in tanks with a wide range of conditions.

Florida Flag Fish

The Florida flag fish will feed on green hair algae. This fish is mostly peaceful, but it can be aggressive when it’s time to spawn. It is also known to eat black beard algae and other fuzzy kinds.

How To Get Rid Of Green Hair Algae On Moss

Introduction: Moss is a popular choice for planted aquariums and terrariums because it is relatively easy to care for and provides a naturalistic look. However, green hair algae can quickly take over a moss-based aquarium, smothering the plant and causing it to die. This type of algae is especially difficult to control because it can spread quickly and is resistant to many common algae-control treatments. Here are 7 things you can do to get rid of green hair algae on moss.

Don’t Over-Water Your Moss

Green hair algae love damp conditions, so it’s important not to over-water your moss. Allow the top layer of moss to dry out completely between waterings.

Increase Air Circulation

Poor air circulation can also lead to an increase in green hair algae growth. Be sure to provide adequate ventilation for your moss.

Prune Regularly

Regularly pruning your moss will help remove any areas heavily infested with green hair algae. Toss any affected moss clippings in the trash to prevent the algae from spreading.

Keep an Eye on Your Fertilizer

Too much fertilizer can also lead to an increase in green hair algae growth. Be sure to follow the manufacturer’s directions carefully when applying fertilizer to

Use a Copper-Based Algaecide

If green hair algae is a persistent problem, you may want to try using a copper-based algaecide. These products are available at most garden centers and hardware stores.

Introduce Algae Eaters

Certain types of fish and invertebrates will feed on green hair algae. Introducing these predators into your moss can help to keep the algae population in check.

Remove Affected Moss

As a last resort, you may need to remove all of the moss from your aquarium and start over. This is a drastic measure, but it may be necessary if the green hair algae problem is severe.

By following these tips, you can help to get rid of green hair algae on your moss and keep it from coming back.

How To Get Green Hair Algae Off Glass

To keep your aquarium glass clean and clear. It can be hard to stop green hair algae from growing on your glass, and it’s usually not a sign of a bigger problem. But using the wrong tools or scrubbing too hard can break your aquarium glass, so it’s important to know what to use and how to use it.

1. Algae Scrapper

An algae scraper is a tool with a blunt edge that is used to scrape green hair algae off of the glass. Aquarium scrapers come in many different sizes and shapes. Some use titanium cards with special blades, while others use plastic cards. 

2. Toilet Paper

You can also wipe algae off your glass with a paper towel. Just wet a paper towel and rub the green hair algae off with it. Make sure you use a paper towel without lint so that you don’t end up with paper pieces in your aquarium.

3. Scrubbing Pad

You can use a scrubbing pad to get rid of tough algae. Just wet the scrubbing pad and scrub the algae off with it. When you’re done, make sure to rinse the area well with clean water.

Magnet scrapers are a great way to get algae off the glass of your aquarium. Just put the magnet scraper on the outside of your aquarium and move it around to get the algae off. You and your fish are both safe when you use this method.

No matter which method you use, make sure to rinse the area well with clean water when you’re done. This will get rid of anything that could hurt your fish.

How To Get Rid Of Green Hair Algae In Freshwater Tank On Plants

Green hair algae will also happily grow on a plant that grows slowly. If you have green hair algae on your plants, there are a few things you can do to get rid of it.

Take Off the Leaves That Are Affected

If the green hair algae are only on a few leaves, you can take off those leaves and throw them away. This won’t kill the hair algae, but it will get rid of it from your plant.

Don’t Give Your Plants As Much Fertilizer

If you give your plants too much fertilizer, it could be making the green hair algae grow. Reduce how much fertilizer you are using and see if that helps.

Don’t Add More Light

For green hair algae to grow, they need light. If you stop giving your aquarium more light, it will help stop green hair algae from growing.

Use an Algae Eater

If your aquarium has an algae eater, it will help keep the green hair algae in check. The Siamese Algae Eater or the Otocinclus are good choices because they are cheap and common hair algae eaters.

Use a Chemical Treatment

You can kill green hair algae with a few different chemical treatments. Some of these are copper sulfate and algaecides. Make sure to carefully follow the instructions on the package.

Your aquarium plants will thank you for taking the time to get rid of the green hair algae. With a little effort, your plants will be healthy and free of algae.

How To Manually Remove Green Hair Algae

If you’ve been noticing some green hair algae in your aquarium, don’t worry – this is a common issue that many aquarium owners face. While it’s not necessarily harmful to your fish or plants, it can be unsightly and difficult to get rid of. Luckily, there are a few things you can do to manually remove green hair algae from your aquarium. in no time!

Brush It 

Use a stiff brush to scrub the algae off of rocks, decorations, and other surfaces in the aquarium. A toothbrush or nail brush can work well for this.

Pick It 

Use your fingers or tweezers to pick algae off of plant leaves and other surfaces. Be careful not to damage the plants as you do this.

Vacuum It 

Use a gravel vacuum or siphon to remove green hair algae from the gravel bed at the bottom of the aquarium. This can be a little tedious, but it’s an effective way to get rid of the algae.

Prune it 

Trim back any plants that are heavily covered in algae. This will not only improve the appearance of the plants, but it will also help to prevent the algae from spreading.

Change the Water

Perform a partial water change to remove some of the algae from the water. Be sure to vacuum the gravel bed during the water change to remove any algae that have settled there.

Adjust the Lighting 

Green hair algae typically thrive in tanks that have too much light. Try reducing the amount of time the aquarium lights are on each day to see if this helps to control the algae growth.

Use an Algae Eater

If all else fails, you can always introduce an algae-eating fish or invertebrate to your tank. These creatures will help to keep the algae population in check and can make a great addition to your aquarium!


What Are Other Simple Cures For Hair Algae?

Increasing the number of water changes you do each week for a few weeks. When you make it easier for plants to grow by lowering the light intensity and at the same time making more CO2 available, you’ll find that mosses and other plants will respond well and grow faster. Hair algae will go away.

Why Is There Green Hair Algae In Planted Tank?

Hair algae can grow when there is an imbalance of nutrients, like when there isn’t enough CO2 or one of the nutrients. But they can happen if there are too many hours of light or if the light above the tank is too bright.


Green hair algae is a type of algae that can grow on a wide range of surfaces. They can spread quickly in aquariums and start to choke out other plants or water life. As we talked about above, algae can grow like weeds in an aquarium if there are too many of the nutrients it needs. Green hair algae can be hard to get rid of, but there are many different kinds of methods and algae eaters that can help. 

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