Brown Algae on Aquarium Plants – Causes & Remedial Measures!

Brown algae on aquarium plants
Brown algae on aquarium plants and all over your tank is a common problem, especially in new aquarium tanks. Brown algae are also known as Silica Algae or Diatoms.
For most new aquarium hobbyists, algae refer to green moss that floats in the water or forms on the rocks, decors, and aquarium glass. However, this brown coating all over the tank, substrate, and decors might cause concern for new hobbyists.
The usual measures to fix this problem are playing with the lighting, dosing algicides, and adding algae eaters to the tank.
However, brown algae on aquarium plants and in the tank are entirely different from the green algae issue. Addressing brown algae is another ball game, and it is relatively easy to arrest the growth of brown algae. First, you would want to identify the causes of the brown algae formation and apply preventive measures. It is far simpler to deal with brown algae issue than with real algae.

What is Brown Algae?

brown algae

Brown-algae is the common name for Diatoms. The aquarists call it brown algae because of the coatings’ color; those clumps of brown hues and skimpy matters sticking on either the substrate, plants, or glass of your aquarium.
Diatoms are too small to see without a microscope. Then how do you see the brown hue in your tank water? Well, brown algae comprise billions of diatoms interlocked with each other.
Diatoms need silica to grow and proliferate; they construct the diatom interlocking blocks with silica. If you use water with a high silicate level in the tank, diatoms have more structure to multiply themselves.
Moreover, in a new tank, there is no rivalry for them as the green algae, or other micro-organisms have not established themselves in the fresh tank. In the presence of silicate and with no one to contest, they build their colonies rapidly.

How to Identify Brown Algae on Aquarium Plants?

Identifying brown algae on your aquarium plants or in the tank is not at all a challenging task as the brown clumpy patches in your aquarium water are quite visible. 

If you already have an aquarium, then you probably have seen those brown-colored blotches on the glass, substrate, plants, or other decorations of your tank. Usually, it’s a thin layer, is a little grainy to the touch. This thin film doesn’t peel off; you will have to rub off to remove the diatoms.

Causes of Formation of Brown Algae on Aquarium Plants

Now you might be wondering what provokes the brown algae formation on aquarium plants even after changing the tank water regularly? Well, to your surprise, there is not a single reason that influences the build-up of brown algae on aquarium plants. Let’s find the root causes to arrest the problem efficiently.

Presence of Silicate in the Tank Water

Silicate is one of the principal components that give ground for the growth of brown algae on your aquarium plants. But why and how? 

Well, the diatoms get their favorite nutrient from silicate, which serves them the proper food and nutrition to reproduce in your tank. If your tank is high on silicate, then brown algae are going to have fun there. But how does silicate come to your tank water? 

  • When you use tap or well water
  • Mixing of salt in your tank water 
  • Leaching of silicates from the live sand and rocks used for decoration

Presence of Nitrates in Your Aquarium Water

Nitrate is another substance on which Brown algae or diatoms can survive; if you have taken care of silicate issues in the aquarium tank and brown algae continue to grow, then the reason could be the presence of nitrate in the tank.

Diatoms grow smoothly in tank water that contains sufficient amounts of nitrate. 

Now you might be thinking that even after using a filtration system, how nitrates manage to come back? The potential reasons for nitrate formation in your aquarium tank water, which you might have been missing, are:

  • From the tap water
  • Using too much plant fertilizer that contains nitrate
  • Fish food is another primary reason 
  • Debris like fish poop 
  • Decaying plants

Presence of Phosphates in the Aquarium

Phosphate is another reason for the formation of brown algae on aquarium plants, which add to your aquarium cleaning duty. But how does phosphate come to your tank water? 

Phosphate is one of the essential nutrients for all living beings. It’s there in every living thing, hence the presence of phosphate in your tank water. However, in an eco-system such as an aquarium with different living beings, the phosphate level might cross the limit. It is paramount to test the water regularly with a test kit and carry out necessary corrections in the water parameters.
The recommended phosphate level is below 1 ppm (Parts Per Million) for the freshwater aquarium tank and the fully planted tank below 3 ppm.
Well, check out the factors responsible for phosphate introduction to your aquarium.
  • Leftover uneaten fish food in your tank 
  • Dead algae 
  • excess KH and pH  
  • Using tap or well water 
  • Fish wastes 
  • Decaying plants 
  • Dead fishes and invertebrates

Light Intensity Also Matters

Though brown algae don’t care about whether it is a freshwater or saltwater aquarium, it cares about your tank’s lighting intensity. Brown algae love a low lighting environment. In a brightly lit tank, the green algae take over the brown algae.

Since they are diatoms, lighting conditions highly impact their existence. A combination of low-intensity light and adequate nutrients like phosphate, nitrate, and especially silicate is the favorite breeding ground for brown algae. 

So, what about the lights in your aquarium? Is it dim or bright? Check that first!

Is Brown Algae Harmful to Your Fishes?

You might be thinking that whether the brown algae on aquarium plants harm your fish or not! Chill! It won’t. Brown algae are entirely safe for your fishes. Do you know what the surprising fact here is? The brown algae can make your fishes healthy. Wondering how? 

Well, the diatoms consume CO2 and give out pure oxygen in the water, which increases the oxygen level in your tank. Isn’t that great? Properly oxygenated water is too important to give your fish the best breathing environment. 

Also, these brown algae enhance the liveliness of your fishes in case the oxygen is too low. Your fishes are not at all going to bother about them being in the water.

However, it can pose a problem for your beloved plants and corals, as brown algae consume all their nutrients, depriving them of adequate nourishment. Also, it blocks sunlight from penetrating the aquarium, which causes the decaying of the plants, ruining the ultimate balance of the tank water.

Now, does this contrasting behavior of brown algae towards your fishes and plants confuse you? Well, the best thing you can do is keep your water sufficiently oxygenated so that your fishes don’t require brown algae for their growth.

Which Fishes Eat Brown Algae?

brown algae eating fish

To remove those brown algae patches from your tank, do you know what the smartest trick can be? Add some sucker-mouth fishes to your tank! 

These aquatic species are excellent in eating off the brown algae on your aquarium surfaces, such as glass, rocks, substrates, decors, plants, etc. You can pet Plecostomus, Otocinclus Catfish, Chinese Algae Eater, and other species of suckerfishes to do away with those stubborn brown algae patches in your fish tank.

Do Snails Eat Brown Algae?

Yes, they do! You can add snails like Malaysian Trumpet snail, Nerite snail, Mystery snail, Ramshorn snail, or Trochus snail in your fish tank to remove brown algae in your aquarium.

Do Shrimps Eat Brown Algae?

Of course, they do! Amano shrimps,  Red Cherry Shrimps, Ghost Shrimps are some of the most efficient brown algae eaters. They can clean brown algae on aquarium plants, rocks, and other decors. However, they aren’t capable of cleaning your tank’s glass, as they do not have the necessary tool to do so.

Best Ways to Remove Brown Algae on Aquarium Plants

Brown alga is a common phenomenon in a new tank; Almost every novice aquarist will encounter it, and the problem settles down itself with a given time. It is a natural part of your aquarium or in any water body. 

However, when the brown algae grow uncontrollably, then it poses a real problem to other plants and corals in the aquarium.

Do you know how harmful brown algae on aquarium plants can be? Extreme overgrowth of brown algae on live plants and corals can make them die. Also, brown algae coating on other non-living objects like glass, substrate, and decors can impose problems. 

How to eradicate brown algae?  

Well, for your convenience, I have brought forward a few fool-proof tricks to clean off brown algae from your aquarium.


Removing Brown Algae on Aquarium Plants and Corals

Water is the best weapon to get rid of those slimy unwanted brown algae. Use a turkey baster and blow water through it on the brown algae layers over your corals. It will disseminate the algae throughout the tank water, which will be later thrown out by your aquarium’s filtration unit.

In live plants, use a soft sponge and rub off the brown algae coatings carefully to disperse them in water. Then, those algae streaks will be collected and filtered out through the filter equipped in your tank.

Removing Algae from the Glass of Your Fish Tank

Brown algae don’t care whether you are using a glass fish tank or an acrylic one. They will adhere to your glass aquarium, giving it an ugly, dirty look. So, what should you do to remove them?

Very simple! Apply a single and smooth stroke, wiping off from one side to another or from top to the bottom of the aquarium’s glass. It will scrape off a maximum amount of algae particles, leaving behind only a little to float in the tank, which can later be taken care of by the filtration unit. You may use a small squeegee for wiping away brown algae from the front of the fish tank. 

Removing Brown Algae from the Substrate

Besides the growth of brown algae on aquarium plants, every form of aquarium substrate, whether it is pebbles, sand, or gravel, can promote algae formation. But how do you clean it? Check out the tips below. 

Sand Substrate

If you are using a sand substrate, brown algae will form on its top layer. However, there’s nothing to worry about! You can easily remove it. 

Grab the fishnet and run it over the surface of the sand. Then spoon out brown algae’s top layer and leave behind as much sand as you can. Repeat this action until most of the algae is taken out. 

Well, you can also try vacuuming the brown sludge to suck out the top film of the algae from the sand. What about attaching a pointed object to the tip of your vacuum? Good idea, right? The sharp tip will smoothly separate the brown algae from the sandy substrate.

Pebble/ Gravel Substrate

If you have large pebbles as tank substrate, you can easily remove them and clean the algae build-ups on them separately. But, it’s quite challenging to separate the smaller pebbles and gravel. Hence, in such a case, use a siphon vacuum. 

Vacuum out only the uppermost layer of the gravel substrate and remove all the brown algae sediments. However, make sure you are not removing the good bacteria. If you feel the algae coatings are glued hard on the substrate, remove the gravel’s top layer and wash them thoroughly before placing them in the tank again.

Removing Brown Algae on Fake/ Plastic Aquarium Plants and Other Decors

Do you have too many fake/ plastic plants in your tank for ornamentation? Well, then it can become the most vulnerable spot for brown algae proliferation. So, what can be the solution to this problem? The trick is to use a mild bleach solution. But how will it help?

Firstly, you would want to remove the artificial plants & other ornaments from the tank and then wash them separately. After that, submerge the decors into the 10% bleach solution. For preparing the solution, take ½ cup of bleach per gallon (about 4 liters)of water, then immerse the fake plants & other decors for about 10-20 minutes, and wait for the brown algae particles to float on the water surface.

Now, gently remove the ornaments from the bleach solution, and rinse them firmly using a soft sponge or cloth while washing thoroughly under running water. Tiresome but easy and straightforward method!

How to Prevent Returning of Brown Algae on Aquarium Plants?

Once you are done removing the brown algae patches from your fish tank? I am sure you must have!

But now the question is, how do you stop brown algae from making a comeback to your aquarium. Well, here I have enlisted a few prevention methods for brown algae on your aquarium plants.

Use the Right Water Type and Change it Often.

Do you use well water or tap water for your aquarium? 

The water you use serves as one of the primary sources of brown algae proliferation in your tank. So, ensure using RO water that does not contain any impurity and treat the water with a conditioner making it a suitable choice for your aquarium tank. 

Also, periodic changing of water is imperative to keep your fish tank clean and prevent the formation of nitrate, silicate, and phosphate, which, in turn, hinders the growth of brown algae on aquarium plants.

Maintain a Proper Filtration Rate

Are you a novice aquarist and don’t know whether you are using the right filter for your aquarium or not? Well, then it may be the real problem. 

Your tank needs adequate filtration to maintain a healthy aquatic environment. While choosing the filter, you would want to ensure a minimum of 10 cycles per hour; meaning, your filter should circulate the entire water in the aquarium tank ten times in an hour. 

For example, if your tank capacity is 20 gallons (75 liters), your filtration capacity should be 200 gallons (750 liters) per hour.

You can use a sponge filter or a hang on the back filter or protein skimmer, a canister filter, an under gravel filter, a dry sump filter, a combination of filtration, etc., depending on the size of your tank and the types of stocks in the aquarium tank. After thorough research, all the information is available online; read more than one article or recommendation to draw your conclusion.

Avoid Silicate:

Silicate is the primary source for diatoms to thrive in your aquarium. Silicates enter your aquarium system in many ways; most tap water contains silicate. It can hitchhike with your sand and gravel substrate, also through rocks and other decors. 

It isn’t possible to remove the completely leaching of silicate from the sand substrate; however, you can reduce it considerably by washing the sand thoroughly with bleach and rinsing thoroughly, and soaking in conditioned water a few days before adding the sand to the aquarium tank.

Another means for silicate to enter your aquarium tank’s eco-system is when you have specimens of certain types of African Cichlids and other livebearers, you would need to add some salt to the aquarium. Ensure to add the salt meant for aquarium use and not the table salt; table salt contains a certain amount of silicate in it.

Enhance the Water Flow

Besides filtration, the water movement in your tank also needs to be appropriately checked. Well, diatoms don’t like to swim much; they thrive in still water. And that’s why they stay piled up, forming a coating over the different objects in your tank. 

If the water movement is increased adequately according to your stock requirements, brown algae face difficulty staying clumped together in one place, and this slows down their proliferation rate. But how do you achieve a higher water flow rate? You could use an air stone with a pump or current maker; there are so many options available to create water movement in an aquarium tank!

Avoid Overfeeding Your Fishes

In case you notice that your fishes are not eating all the food you are giving them, it will be leftover on the substrate itself. Studies say overfeeding of fishes causes rotting of the excess food, leading to nitrate accumulation in tank water. And do you know this aid brown algae formation on your aquarium plants? 

A thumb rule in feeding aquarium fish is to feed as much quantity that your fish can eat in 3 minutes; with a little trial, you will know the amount required by your fish.

Improve Lighting

Enhancing lighting in your aquarium will encourage green algae growth in your tank, preventing or giving a tough competition to brown algae. Controlling green algae is more manageable than taking control over brown algae or diatoms. After all, not all fish or invertebrates enjoy diatoms.

However, plenty of fish species and invertebrates enjoy munching on green algae; in fact, green algae is their primary nourishment for numerous species. However, it is important you don’t the green algae to bloom because it reduces the dissolved oxygen in the aquarium tank and this can lead to the drowning of your fish.

Also, enhancing lighting 12 hours a day helps the other plant kingdoms thrive well; thriving of other vegetation reduces the nutrient supply to diatoms in the aquarium.

Introduction of brown algae eaters into your aquarium tank:

brown algae eaters

Introducing species that consume brown algae is another way to prevent the brown algae from proliferating.

Sucker-mouth fish, Bristlenose plecos, pufferfish, and several catfish varieties will readily munch on brown algae on aquarium plants and in the tank. You can also introduce invertebrates such as Amano Shrimp, Red Cherry Shrimp, Ghost Shrimp, etc. 

Snails such as Nerite snails, Mystery snails, Ramshorn Snails, and many more can do the job impeccably. 

Brown Algae on Aquarium Plants – A Wrap-Up

Diatoms or Silicate algae or brown algae is a pain but not dangerous if it’s under control. As a matter of fact, many aquarium enthusiasts love it.

Brown algae or silicate algae is an issue every new tank passes through. Generally, it clears up with time; as soon as the plants and other microorganisms establishes themselves in the ecosystem. 

Just take care not to let it grow over out of control. Keep a check on it with one or a combination of methods suggested above.

Enjoy your newly set-up aquarium! Also, you could share with us your experiences here below!

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