How To Remove Fish Tank Algae (Green, White, And Brown)

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The type of algae we are focusing on here is fish tank algae and the quest is to discover everything there is to know about it and most importantly, how to get rid of it.

How To Remove Fish Tank Algae (Green, White, And Brown)

People hear the term algae all the time and when most people think of it they think about that nasty green layer of plant matter that forms at the top of their swimming pool when it isn't properly treated. That’s not the kind of algae we are talking about though, or to be more precise it isn't the setting we are aiming for.

When it comes to fish tank algae, it can be a real nuisance because it has the ability to use light and nutrients in the water in order to grow endlessly, and if left untreated and unmaintained it can grow out of control, eventually enveloping the whole fish tank. (This tool is great for getting rid of algae). Keep on reading to find out exactly what algae is, how it gets in your fish tank, if it is dangerous for your fish, as well as some different methods and products that can be used to get rid of it.

Magnetic Brush 9.5/10
KEDSUM Scrubber Brush 9.3/10
Plastic Handle Sponge Brush 9.1/10

Note: Clicking on the above links will take you to further information, current prices and customer reviews on Amazon.

Our Top Pick & Best Product To Remove Fish Tank Algae

Magnetic Aquarium Fish Tank Glass Algae Glass and Acrylic Cleaner

This is a great tool for keeping the algae out of fish tanks and a pretty popular option for good reason (You can check the current price at Amazon here). This is simply a magnet that attracts algae as it passes over the algae. This type of algae cleaning tool can really only be used for the glass of the fish tank but not for the substrate, plants, or other things like rocks and ornaments.

It’s a really convenient tool because all you have to do is drag it along the glass to pick up the algae, it has a no scratch felt lined handle to make sure that the fish tank will not get scratched or damaged. It’s really convenient because you don’t actually have to put your hands into the aquarium.

Simply insert the magnetic scrubber into the aquarium and drag the magnetic handle alongside the outside of the aquarium to make the scrubber follow on the interior. This product is also really convenient because it features a floating scrubber that when it is not attracted by the magnet on the outside will float to the surface of the water so that it does not have to be manually retrieved from the bottom of the fish tank.

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What Is Algae?

Algae are all plants that are commonly found in water. They can be very large such as seaweed and kelp that can grow to over several hundred feet in length and they can also be very small, even microscopic in size. The main type of algae that is found in aquariums is microalgae, or algae that is very small and tends to grow on the bottom of the tank as well as on the sides.

The most common type of micro algae found in fish tanks are green algae, white algae, and brown algae too (red is covered separately here). Algae are all very important to all ecosystems on earth. They provide for a very large food source for most aquatic animals and they also account for over 70 percent of all oxygen that is created, oxygen which humans and other animals need to survive.

Algae is very resilient and can grow in salt water, brackish water, as fresh water too, not to mention that they can grow in virtually any condition of water including clean water, chemical runoff, animal runoff, and in virtually any other type of contaminant that could be in water.

Almost all forms of algae grow through a form of photosynthesis where they convert sunlight, carbon dioxide and other nutrients such as nitrogen and phosphorus into biomass, biomass being the food that the plant needs to survive and grow. Some forms of algae can also grow through heterotrophic methods, meaning that they can use starches and sugars to grow. Some forms of algae can even use autotrophic growth methods (photosynthesis) as well as heterotrophic growth methods in combination.

There are tens of thousands of different species of algae and one of their main drawbacks when it comes to being in aquariums is that all forms of algae reproduce much faster than any other plants known to man.

There are a few benefits that algae come with, however of course not when your own fish tank is involved. Algae are great for recycling carbon dioxide and turning it back into breathable oxygen. Also algae produce very high yields of biofuel that burns much cleaner than other fuels such as fossil fuels. The biofuel made from algae can also be used to create food or feed for farm animals. Algae can actually also be used to purify water systems and even to create a variety of products such as lubricants, plastics, cosmetics, and fertilizers among other things.

How Does Algae Get Into A Fish Tank?

To be fair the algae didn’t really get into your fish tank, or in other words it didn’t appear out of nowhere and just hitch a ride. The algae in your fish tank don’t come from the other plant life, the fish food, or even from the fish itself. Any and all algae that may appear in your fish tank, whether white, brown, or green, appears because it has always been in the water and just needed a chance to grow.

What Causes Algae In Fish Tanks?

Seeing as the algae found in your fish tank is a type of microalgae, meaning that it is very small, it is safe to assume that it has always been in the water. All water contains bacteria, micronutrients, and microalgae too. The reason we never see algae in our drinking water or in our toilets is because it doesn’t get a chance to grow. Everywhere water is treated with various chemicals that kill of most bacteria, the main one being chlorine (We have covered a seperate post here on our top 6 dechlorinators).

Chlorine however does not have the ability to kill microalgae and therefore it is always present in the water supply. The reason it doesn’t grow or get a chance to grow is because there are no starches or sugars in our tap water. Also the water we use spends most of its time in a dark pipe where photosynthesis is no feasible.

All of this being said if you leave a cup of water sitting still for a few days, especially if you leave it in the sunlight, it will start to grow algae. Therefore the algae in your fish tank got there when you put water into the tank, and it got a chance to grow thanks to the abundant light available as well as the mass of nutrients in the water.

In other words there is nothing you can do to prevent algae from growing in your fish tank, but you can do several different things to remove it.

A protein skimmer can also help keep your water clean, check out our article on Protein Skimmers.

Is Algae Harmful To My Fish Tank?

In all reality, while algae may be somewhat unattractive, it isn’t actually all that bad for your aquarium. The main reason that people don’t like having algae in their aquariums is because it can make the fish tank look dirty and unclean, not to mention that it can make the water look unclear and slightly foggy. (A cloudy aquarium is quite common and here is how to fix it).

For one, algae is good in small numbers because it can purify water. Fish hate waste in their water or dirty water in general and fish also need fresh oxygen. Fish tank algae has the ability to filter out some bacteria, chemicals, and toxins that are harmful to fish, not to mention that they produce oxygen which your fish needs to breathe. Besides that algae is also useful as a food source because many fish like to eat the stuff.

One of the drawbacks of having algae growth in a fish tank is that it can out-compete aquarium plants. Algae does require nutrients to grow and it will suck them out of the water, thus leaving less nutrients for your aquarium plants. Therefore if you have a planted aquarium it is recommended to have quite a few plants so that they will out-compete the algae for the available nutrients.

Another problem with algae is that it tends to grow very fast and can quickly overtake an aquarium if it isn’t maintained for a while, especially so when lights are left on for a prolonged period of time.

Types Of Aquarium Algae & What Causes It

Before we look at how to get rid of fish tank algae, let's first look at the common types;

Green Algae

There are actually several different types of green algae that can be found in aquariums. They can take the form of green hair algae, green spot algae, and green water algae that turns the fish tank into a green fog. Controlling this type of algae is a little easier said than done because each one has slightly different causes of growth and each one requires a slightly different treatment.

The most effective way to take care of green algae is by using a fish friendly algae killing chemical. On a side note the problem with algae killing chemicals is that many of the plants in a fish tanks can also be negatively affected by them.

Green water is usually caused by too much light, high ammonia levels (this post cover how to lower ammonia levels), disturbance of dirty substrate and over all high nutrient levels. Green spot algae can be cause by high phosphate levels and low carbon dioxide levels, as well as too much light. And green hair algae can be caused by low nitrate levels, low carbon dioxide levels, and too much lighting.

How To Get Rid Of Green Algae

To get rid of any and all of these green fish tank algae you will need to find the proper balance of lighting, carbon dioxide levels, and nutrient levels. Another good tip is to keep your filters and the tank itself clean, also change the water fairly often.

White Algae

White algae is a fairly common form of fish tank algae. It isn’t dangerous for the fish but it can be a nuisance because it grows quickly and can envelop your fish tank. This type of algae is most often caused by having too much sunlight as well as improper nutrient levels.

White algae will usually take the form of a slick film or even something like a web. This kind of algae is often found growing on fish tank ornaments, driftwood, and rocks, but is usually not found on the glass of the tank.

How To Get Rid Of White Algae

White algae are best removed by changing the water often and keeping the filters well maintained as well as by removing it with an algae scrubber. It can also be treated by standardizing the nutrient levels and sunlight levels in your fish tank. Another good way to get rid of this type of algae is to get a few fish or snails that feed on it (We like the Zebra Nerite Snail, more on it here).

Brown Algae

Brown algae is perhaps the first type of algae growth that you may experience in your fish tanks is probably the most common. This brown algae can take the form of light fluff or as spots. It tends to grow on the glass, the substrate, rocks, plants, and pretty much anything but the fish themselves.

This type of algae usually grows in newly established fish tanks and more often than not it will disappear completely when the fish tank stabilizes and the parameters of the tank have been brought up to standard.

There are a few different things that can cause brown algae to grow in your fish tank. These causes include low light, old light tubes, high levels of nitrates in the water, high levels of phosphate (which usually occurs due to overfeeding the fish), and a poorly maintained aquarium filter. Thankfully this type of algae is not too hard to get rid of.

How To Get Rid Of Brown Algae

All you have to do to get rid of brown algae is to turn up the light intensity and the duration for which the lights are on, replace old or worn out lights, change the water regularly, decrease nitrate and phosphate levels, stop overfeeding the fish, and most important of all, keep the filter clean and well maintained.

Other Recommended Products To Get Rid Of Algae

KollerCraft TOM Algae Scraper Multi-Tool

This is another great tool that is very convenient for algae removal. Once again it has some good customer reviews and has a reasonable price tag too. It is a multi-tool and comes with several algae cleaning attachments.

It is safe for glass aquariums and can actually not be used on plastic ones. It has a great 22 inch long corrosion resistant handle that keeps your hands dry while cleaning the algae. It comes with a great stainless steel algae scraper attachment for simple algae buildup, and for those denser and harder buildups it also comes with a hard plastic scraper.

The third interchangeable head included in this multi-tool algae scrubbing kit is a small shovel to enable the user to pick up items that have fallen to the bottom of the aquarium.

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Mag-Float Glass Aquarium Cleaner

The Mag-Float is a fantastic tool for cleaning fish tank alage because it is very easy to operate. All that you have to do is to insert the scrubber into the inside of the aquarium and use the magnetic handle to guide it along the outside.

Anywhere that you move the magnet on the outside, the scrubber will follow on the inside. This scrubber also has a special floating ability that means it won’t sink to the bottom of the tank and it also makes it a lot easier to guide around corners.

This is one of the number one choices for cleaning algae off of the glass in a fish tank for many people. The customer reviews definitely speak to this fact, not to mention that the price tag isn’t even too high!

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How To Prevent Algae Buildup

There are a few different tips that you can follow in order to prevent algae buildup. One of these tips is to not overfeed your fish. Many types of algae grow quicker and better when there is debris and extra nutrients floating around in the water, so only feed your fish as much as you know they will eat.

The next way that you can help prevent algae buildup is by getting fish, such as catfish, that love to eat the stuff; certain aquarium snails work really well too. Also, before adding fresh water to your aquarium you should test the tap water to make sure that your water isn’t too high in nitrates or phosphates that will encourage the algae to grow; the best bet is to use a tap filter.

What Stops Algae Growth

Another tip would be to control the lighting in your aquarium. A large cause of algae growth is over-lighting, so turning the light cycle back a bit can definitely help. Another good tip is to increase the competition by adding more plants.

The less plants you have in the water the more nutrients there are for the fish tank algae to be sustained with. Having more plants will restrict algae growth by taking away the valuable nutrients they need to survive. You can also help prevent the buildup of algae by regularly changing the water as well as the filters in your fish tank to ensure that there aren’t too many extra nutrients floating around.