A healthy aquarium is an ecosystem in itself, and while aquarium owners would want only a select few organisms to thrive in it, there can be some unwanted guests from time to time.
One of the most unwelcome additions to any fish tank is brown algae. It can render the most beautiful tank an eyesore in a matter of days. This pesky intruder can takeover aquariums at such a fast rate and in a manner alarming enough, some hobbyists can even end up contemplating abandoning the hobby.
Thankfully, there is no need for such drastic measures, and like with any problem, the key to avoiding brown algae or getting rid of them lies in the knowledge associated with them.
Let’s look at the different causes that can promote the growth of brown algae. This will help in avoiding the problem in the first place. We will also look at ways of permanently removing it for the benefit of those already suffering from an invasion.
What is Brown Algae?
The name Brown Algae is a misnomer in the aquarium trade. True Brown Algae are found in large marine ecosystems and include things like seaweeds.
In the context of a home aquarium, brown algae refer to single-celled diatoms scientifically known as Bacillariophyceae. They can also be referred to as the Silica Algae and can be found in both freshwater and saltwater aquariums.
These unicellular creatures form large colonies when the conditions are right and this is what appears as the brownish algae to the naked eye. They form clumps or patches of brown powdery stuff that can settle on pretty much all the surfaces available inside the aquarium.
Brown algae does not attach themselves too strongly and can be easily wiped away. However, doing so without identifying the root cause and remedying it will only force the brown algae to reappear eventually.
Is Brown Algae Dangerous?
Some algae can be incredibly dangerous both for the health of the fish and anyone who takes care of the aquarium but the brown algae, thankfully, does not fall under that category. Many fish and inverts even consume them vociferously as food. The only downside to these algae is that they can turn the aquarium into an eyesore with severe infestations appearing as if the aquarium has been filled with swamp water.
What Causes brown algae?
There are four major causes that can lead to a bloom of these algae. These are:
- Excess Silicates: This is the most common cause that promotes the growth of brown algae. These algae thrive on silicates which they use as food. Excess silicates can speed up the bloom of algae at an alarming rate. Silicates are normally present in tap water. They can also be released by live rocks and live sand.
- Excess Nitrates: Even if there are no silicates in the water, these diatoms can still survive on Nitrates. This is the final product of the nitrogen cycle and it starts accumulating with time. When partial water changes are done sporadically, the nitrate levels can rise to a point where the aquarium can become an attractive habitat for algae.
- Excess Phosphates: This is another alternative food source for the algae. Phosphates can find its way into your aquarium through multiple ways but the most common ones include dead and decaying plant and animal matter, decomposing food, and by being naturally present in tap water.
- Improper Lighting: This one is a bit debatable as the jury is still out on it. There have been some reports that improving lighting can get rid of brown algae in planted tanks. The most plausible explanation is that under poor lighting, all the plants have to compete for the limited amount of lighting and this can cause an imbalance of nutrients. Plants may not be able to absorb nitrates and phosphates at a quick enough rate leaving the water rich with these chemicals which acts as an open buffet for the brown algae.
How to Prevent Brown Algae?
Sticking to the basics of good aquarium maintenance is where you need to start. Make sure that the filtration is adequate and that you do a partial water change at least once every two weeks.
Carefully monitor the water for the various chemicals that can aid in brown algae growth. If your tap water naturally contains silicates or phosphates, make sure to treat the water first before adding it to the aquarium.
There are many good and proven products that are commercially available for aquariums that can neutralize these chemicals.
Another important ally in the fight against brown algae is a strong water flow. These algae are terrible swimmers and as long as there is plenty of water circulation, they won’t get a chance to anchor themselves somewhere which they need to do before they can reproduce and multiply.
As alluded to earlier, there are plenty of fishes and invertebrates that you can add and these will munch on any stray brown algae. Freshwater options include snails, Amano Shrimps, Oto Catfish, Plecos, Siamese Algae Eaters, and Chinese Algae Eaters.
Plecostomus 
Chinese Algae Eater
Finally, ensure that the aquarium receives adequate lighting especially if it has live plants just to be on the safe side.
How To Remove Brown Algae?
In the unfortunate event of your aquarium already being infested by brown algae, do not worry and definitely do not think about quitting the hobby.
Identify the root cause of their infestation in the first place and then use that knowledge to make the aquarium as inhospitable to these algae as possible. This will starve them and they will start dying off.
All the brown stuff will still look quite unappealing. Wipe all the surfaces that you can to remove the layer of brown algae attached to them. Use a Siphon Vacuum to remove them from in-between the substrate.
For any live plants and rocks, use something like a turkey baster to gently wash or rinse the algae off. For other forms of decor such as fake plants and rocks, soak them in a solution of half a cup of bleach in a gallon of water for about 20 minutes. Make sure to thoroughly wash them before adding them back to the aquarium.
Finally, carry out a water change to remove any strays. As long as you ensure that the aquarium doesn’t become hospitable to these algae, there should not be a recurrence.
Brown algae conclusion
As you can see, while brown algae can certainly be an eyesore, it can be easily controlled. Don’t stress too much if your aquarium gets inflicted. Just follow the steps in this article and you should be well on your way to having a beautiful aquarium once again.
