Brown Algae In A Betta Tank – How To Deal With It!

Estimated read time 10 min read

We’ve all been there…

At one time or another, you’ll see brown stuff growing in your fish tank!

This is Brown Algae.

Unfortunately, Brown Algae can cause a variety of problems in your aquarium.

For one thing, cleaning your tank takes a bit more effort because it clings to things in your tanks like the gravel, glass, and decorations.

Second, it looks horrible and contributes to the overall uncleanliness of your aquarium.

If your goal is to have a clean and clear aquarium, you know what a pain Brown Algae can be.

Thankfully, there are few things you can do to help get rid of Brown Algae as well as a few preventive measures to ensure Brown Algae doesn’t return.

Below, we will discuss all of this.


Some Things To Help Get Rid Of Brown Algae In Your Fish Tank

Is Brown Algae Bad For Betta Fish?

Brown Algae in your fish tank is neither good nor bad, it’s more of a nuisance than anything else. It’s not exactly harmful or threatening, but it is an unpleasant sight to see.

Usually, Brown Algae is found on the tank glass, decorations, and gravel from there, it has a tendency to spread.

If anything, it serves as a warning sign of a potential maintenance issue that you’ll need to address.

What Does The Existence of Brown Algae Mean?

Depending on your aquarium there can be few factors that will lead to the growth of Brown Algae.

For example:

Brown Algae is often found in new tanks, where a stable ecosystem has not yet had a chance to develop.  

Many new tanks will naturally take care of Brown Algae as the nitrogen cycle works it magic as helpful bacteria mature.

But, if you feel the algae growth getting out of control, it’s likely time for a cleaning and working on some preventative measures.

Did you know: Green algae, and various species of plants, will often eliminate Brown Algae in their similar pursuit of shared nutrients in your tank.

What Causes Brown Algae In A Betta Tank

So why is my Betta tank turning brown?

Well, a variety of factors could be contributing:

  •      Poor oxygen circulation
  •      Insufficient lighting
  •      Nutritional excess
  •      An imbalance of nitrates and silicates

Watch this video to learn more.

Let’s explore each one of these issues separately and why the problem starts.

Why is There Brown Algae in Your Fish Tank?

Poor oxygen circulation

Low levels of oxygen can lead to the creation of Brown Algae and usually a result of overstocking your aquarium.

If your tank is experiencing low levels of oxygen, you can usually tell due to the spread of Brown Algae or by closely gauging the body language of your fish.

Your fish may show a few common symptoms:

  • Restricted or decreased movement
  • Less appetite
  • Erratic or frantic breathing from gills
  • Desperate breathing from the surface

While investigating these symptoms, remember that some fish are in their natural state while intermittently breathing from the surface.

Betta Fish, for example, are known for breathing at the surface. You should have a good idea of how your fish normally behave, before assessing them.

Insufficient lighting

Your Brown Algae problem could be lighting related which is why it’s important to ensure that your aquarium has sufficient light levels.

One way to make sure the right balance of light reaches your aquarium is to purchase a light timer. That way, your tank is guaranteed to receive the perfect amount of light.

Nutritional excess

You will want to assess your aquarium in terms of overcrowding. Aquariums overcrowded with plants or fish, or a combination of both, are hot spots for the growth of Brown Algae.

Overcrowded tanks have a tendency to lead to an overabundance of fish-waste (excess nutrients), which can contribute also to the development of Brown Algae.

Both food and waste can accumulate quickly, leading to harmful bacteria which in turn may create Brown Algae or this waste will lead to ammonia, which is very toxic to your fish.

An aquarium that is regularly cleaned will at least curb the rapid growth of Brown Algae if, in fact, it does exist.

An imbalance of nitrates and silicates

High amounts of nitrates and silicates can also contribute to the growth of Brown Algae. Make sure that the water used to fill your tank is not teeming with silicic acid.

Nitrates, on the other hand, are frequently found in aquariums as they are a byproduct of the nitrogen cycle.

Nitrates need to be removed from your tank through regular water changes.

Click here to see some pictures of brown algae in a fish tank.

What Can You do About The Brown Algae in Your Fish Tank

If you have a Brown Algae problem make sure you are providing a sufficient amount of light. Shady, unlit areas often contribute the most to the spread of Brown Algae.

Up to 8 hours of sufficient lighting on a daily basis is recommended. Healthy amounts of lighting will of course vary, depending on the ratio of plants to fish in your aquarium.

On the other hand, excessive levels of lighting can also contribute to the growth of other forms of algae.

Every tank is different and you’ll need to find the proper balance of lighting suitable for your tank.

Take into account:

Your fish, the type of plants you have, where your aquarium is located.

Watch this video to learn more

How to Prevent and Stop Brown Algae in a Fish Tank

There are a few ways that you can prevent Brown Algae from even becoming a problem in your tank.

Here are a few things to do:

It’s great to know how to prevent this ugly problem, but what if you already have it in your tank.

Lucky for you that’s next up.

How To Get Rid Of Brown Algae In A Betta Tank 

There are several ways in which you can get rid of Brown Algae.

Some fish owners, simply allow for their fish to eat it up. However, not all fish eat Brown Algae, but some do — and you’ll find a few examples below in the following sections.

Algae eating fish may only serve as a temporary fix because the root cause of your Brown Algae problem is not properly being dealt with.

So what else can you do:

Another more time-consuming way to rid your tank of Brown Algae is removing it piece by piece, rather than by large layers — Sounds like an awesome weekend project!

Gravel vacuuming may be another way to help with Brown Algae if you find most of it developing in or on your gravel.

While vacuuming, light vacuuming is recommended due to the fact that some beneficial bacteria are living in your gravel.

Many aquarium owners give their tank a sufficient vacuum whenever the need arises to change the water, that way they kill two birds with one stone.

That said, most Brown Algae will be easy to remove just by wiping it off, vacuuming serves as a more thorough way of removing the Brown Algae burrowed within your tank’s gravel.

Another important measure is to make sure that your aquarium is regularly cleaned and that the water is periodically changed.

Aquariums that are more densely populated tend to require more frequent changes. While others may only require partial water changes.

At a bare minimum, most tanks require at least 10% of their water to be changed weekly.

Remember that adding water, is not the same as replacing water. Just because your aquarium’s water is clear, doesn’t necessarily mean that it’s clean.

Can’t Get Rid of Brown Algae in your Fish Tank – Try This!

If you’ve gone through the above list and still can’t get rid of the Brown beast, what else can you do?

Well, you may want to consider replacing half of your tanks existing water with new water.

Freshwater, which contains trace minerals, will go a long way in terms of promoting vitality for your fish.

Also, you may need to consider using things like powerheads and air pumps for increased water circulation.

Essentially, these are used to promote water flow within a tank, which in turn circulates oxygen more efficiently. It also helps to retain high levels of oxygen and as we mentioned earlier, good oxygen circulation helps prevent Brown Algae.

Tip: Since oxygen replenishment occurs at the surface of a tank, it is good to circulate that water toward the midsections and the bottom area.

A high-powered filter can also help with oxygen circulation. Adding a filter is easy and for the most part hands-free way to improve the environment of your aquarium.

If you find that your filter is not performing optimally, you may need to clean it, add an additional filter, or purchase a more high-powered filter.

Lastly, you could look to a chemical additive that can be used to kill Brown Algae fast. But be wary and do extensive research whenever applying any chemicals or additives to your tank.

Certain chemicals can be harmful to your fish, and/or impair your water’s ability to retain oxygen.

What Types of Fish Eat Brown Algae?


An easy Brown Algae prevention technique is to introduce a few fish that eat algae.

Fish like:

  • Otocinclus
  • Siamese algae eaters
  • Some snail species

These fish are great for keeping Brown Algae to a minimum because they use it as a food source.

In addition to algae eating fish, having a few live plants in your tank is a great way to eliminate many of the nutrients that promote the growth of algae.

This is because the Brown Algae has a tougher time acquiring nutrients when it has to compete with a variety of live plants.

Java Moss and Anubias plants serve as a good place to start.

A Few Algae Eating Fish & Critters

A Few Final Thoughts  

Brown Algae in your tank could be caused by a variety of reasons discussed above.

You should always:

Diagnose your tank and determine the root cause promoting the growth and take an all-encompassing approach while maintaining your aquarium.

Tank maintenance is both an art and a science, and simply dumping new water and food in periodically won’t cut it in terms of taking care of your fish.

By the time you eliminate your Brown Algae, you can thank your lucky stars that it wasn’t the notoriously feared red algae, which is much harder to eliminate.

Fish keeping is a hobby that requires continuous involvement and beginner aquarists shouldn’t be too worried about the threat of Brown Algae.

But you should take action sooner than later if you notice it.

Further Reading:



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