How to Clean Brown Algae off Aquarium Decorations

Fish tanks or aquariums are quite standard in modern households. But if you don’t decorate them, they don’t look that appealing. That’s why people tend to load up their fish tanks with tons of fancy decorations. The variety of these decorations does brighten up the environment a lot. But as you use more and more decorations, there is a chance of the formation of algae in the decorations. Brown algae are one of these nuisances. Read on to find out how you can clean the brown algae off your aquarium decorations.


Types of Brown Algae

If you thought that there is only one type that might harm the ecosystem of your fish, I hate to break it to you because there are more. The algae have multiple colors. The true brown algae are not the ones that grow in your fish tank.

Another type of brown algae is yellow-brown algae. These are the more beneficial types. You will often see these in freshwater ecosystems. They are plant-like, and you won’t find them growing in your home aquarium.

Finally, moving on to the type of brown algae in question. This is the silica algae that usually looks brownish in artificial lighting. This is what the fish store owners would call brown algae. They are also known as Diatoms.


Brown Algae in your Aquarium

The algae that grow in your fish tank or aquarium are the Diatoms. You will find them growing in all aquatic environments inside your home aquariums. Whether it is saltwater or freshwater, these diatoms find a way in.

If your aquarium has high nitrate levels, you will see these brown algae growing. If you have the lighting set to high, these plant-like algae will take over the entire fish tank, which isn’t quite right for your fishes.


How harmful are brown algae?

All you need to do is keep the growth of the brown algae under control. If you let their numbers soar up high, you will have a problem. Sometimes, this type of algae might even be toxic for your fish. They can even cause harm to the other kind of plants you keep in there.

You will see that the algae will sometimes even stick to the glass walls of the aquarium. The colour usually tends to look light to dark brownish.


Why do Brown algae grow in your aquarium?

Brown algae grow inside your fish tank for many reasons. The rapid growth is usually seen in the new aquariums you just brought home. They can grow in your aquarium for the following reasons:

Dark Environment: If you keep your aquarium in the shadow in a dark environment, you might see higher growth. That’s because they need to compete with other water plants to grow in the bright light. So the lighting of your aquarium needs to be set right.

Water Quality: Lower quality of water may be another reason why you see these brown growths in your fish tanks.

Nitrate Levels: Too much nitrate or silica inside the tank will accelerate the growth of brown algae manifolds. Don’t fill up your aquarium with water from the tap if you know what’s right for you. If you don’t have an alternative, use a good quality filter in the tank to cleanse the excess nitrate or silica.

The nitrate level may also rise due to over-filling the tank with more fish or throwing in too much food. So keep your water healthy and fresh to reduce the growth of brown algae.


Preventing the growth of Brown Algae

It’s always necessary to take precautions. You won’t have to deal with the problem if you adhere to the recommended prevention methods. To keep the tank free from brown algae, make sure to ensure sufficient lighting. Following the light around the aquarium at an optimum level will help reduce the chance of the formation of brown algae.

Regularly clean the water of your fish tank and keep the other plants alive. Brown algae can’t compete with them when it comes to absorbing nutrients. So keep them at bay as a protection line against the brown algae. You can opt for a good water filter with reverse osmosis technology too.


6 Ways to Clean Brown Algae off Aquarium Decorations

Moving on to the fun part. This method is for those who have already faced the offensive attack of brown algae inside their fish tanks. All love fish tank decorations as they add vibrant colors to the glass tank and liven up the environment a bit.

But brown algae just won’t let them be! If you regularly clean the tank and water but not the pretty little decorations, you could find yourself in a tight spot because algae will find a way to grow on the unwashed decorations with ease.

So you also need to clean your decorations to keep away from brown algae infestation.


1. Wipe it away!

These types of algae aren’t that difficult to clean most of the time. They don’t adhere to your fish tank glass to firmly. If you get lucky, you might not even require a scrub. Simply wipe the algae off and let your decorations see the light again.

You might require the help of an excellent vacuum to help clean the aquarium gravel. That’s the trickiest part. Try using a siphon to make your job get done quicker. Some fishes eat these algae. So based on your water type, keep a species of that fish as a guard!


2. Soak decorations in hot water

Another simple method of cleaning them is just to dump them all into boiling water. Half an hour in warm water will make the algae loosen up a lot. So more often than not, you will observe that they fall off themselves.

Soak the harder decorations in boiling water since they can endure the temperature. So depending on the material of your decorations, this method might vary.


3. AntiAlgae Solutions

Just take a stroll to your local pet store and ask for aquarium cleaners. These solutions are quite effective against brown algae infestations. The solutions will work like regular glass cleaners. You can easily clean the glass walls of the fish tank with a few drops of solution.

The anti-algae solutions are also incredibly useful to clean the decorations. The chemicals in them make sure you won’t have to deal with them for some time. You can also find some scrubs with these solutions pre-applied. But they are often on the costlier side.


4. Plain Old Bleach

This is one of the more straightforward methods to get rid of your brown algae problems. Every household tends to have a bottle of bleach lying around. Why not use it for cleaning the décor?

Make a solution of water and bleach, and soak the decorations in it for half an hour. Please take the necessary precautions, though. The chemicals in bleach might end up killing the ones you’re trying to protect, the fish.

So make sure to rinse the decorations properly before throwing them back in the tank. Maintain a practice of soaking them in clean water overnight. That should do the trick.


5. Soap and Chemicals

Try to avoid regular soap and detergents while cleaning anything related to your fish tank. These chemicals might end up causing problems for your fish. The residues of ordinary soap stay on even after rinsing, so it is advisable to avoid the use of soap.

Using biodegradable soap is undoubtedly the right choice, though. Biodegradable soaps and chemicals can be used to wash your decorations. You will see that the algae are coming off quite quickly after a little soak.

Just to be on the safer side, rinse the decorations and leave them overnight to dry before throwing them back into the aquarium.


6. Use a Vacuum with a Siphon

This is truly one of the more effective ways to clean up the fish tank. As brown algae can and will grow everywhere, you need to clean the gravels at the bottom of the fish tank too. The uneven surfaces of the gravels are what make things tricky.

Pull out your vacuum and dive right in! If you have a siphon attachment, your job will become a lot easier. You can get into those nooks and crannies quite easily with the siphon, eventually saving a lot of time.



Filling up the aquarium with decorations is a widespread practice. The little decorations liven up the setting a lot. Making the aquarium’s bland glass look visually pleasing is the ultimate goal. But the growth of brown algae does cause problems. You shouldn’t throw out the decorations because of this though.

Brown algae grow in the water, whether it is freshwater or saltwater. So you have to clean the tank anyway. Follow these methods to remove brown algae from your fish tank and take precautions to prevent them from growing again. Keeping things clean is definitely worth your time and money.

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