How To Get Rid Of Algae In Fish Tank

Aquarists have had to deal with algae over the years. Sometimes, they can take over the tank, cause everything to look ugly, and even make your fish less visible.

While they are not entirely bad occasionally, they are not exactly good. For one, algae don’t make your tank look good, and this is why many aquarists try to get rid of them when they show.

If you own an aquarium, you should know how to get rid of algae in fish tanks because they’ll most likely show up in your tank, especially due to some factors you may not know about. Find out how to do so easily.

Read on.

What is Aquarium Algae?

How To Get Rid Of Algae In Fish Tank
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Algae are tiny organisms living in your fish tank and can take over your aquarium in no time, especially if you don’t deal with them. Sometimes, they may look like plants, but they are not the same and can use up nutrients meant for your aquatic plants.

They usually have a green-like appearance, which may automatically make you think they’re green algae, but there are different types. They can make up green mats all over your tank and change the water’s color, making it unattractive.

Now, you may think algae are bad, but not totally. They contribute to the tank’s ecosystem. However, when they get too much, they can cause oxygen depletion, which is bad for your fish.

Other times, they can release toxic compounds into the water. But one good thing about them is that they can be a food source for some algae-eating fish.

Regardless, they shouldn’t stay in your tank for so long. You need to identify them and know how to get rid of algae in the fish tank.

Types of Algae

There are different types of algae, and any could be present in your tank. Although most algae may all look the same, they’re very different.

The following are some of the types of algae:

1. Brown (Diatom) algae

Brown diatom algae usually appear as a dust-like substance in the aquarium. Sometimes, the color could be brown or green, and it hangs onto the aquarium’s walls, substrates, and other surfaces in the tank.

The good thing is that they are easy to remove, and you can do that manually by wiping them using a scrub or sponge. Also, aquatic animals like snails and shrimps like to eat them.

2. Green algae

Another type of algae is the green ones, and they are tough green spots on surfaces or slow-growing plants. They are difficult to clean as compared to the brown ones.

Not only do they leave a green-like mat all over the tank’s surfaces and its contents, but they also lay eggs that are unpleasant to look at. Aquatic animals, like Nerite snails, like to eat them.

3. Blue-green algae

This organism is more like cyanobacteria, and it forms a slimy cover over substrates, plants, and other surfaces in the tank. This alga smells even before it starts forming over areas in the aquarium, and it’s not a likable one.

In addition, it is photosynthetic and can try to take over the tank within one week of appearance, so you’d better get rid of it quickly.

4. Green water

4. Green water
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Algae could also appear as green water in your fish tank and totally change the water in your aquarium. This happens when your tank gets too much light or direct sunlight. Moreover, they quickly reproduce, so you need to be fast with a solution, and you can start by blacking out your tank.

5. Black beard algae

One of the most difficult types of algae to deal with is the black beard algae because not too many fish types eat it. Therefore, it can stay in your tank for too long if you do nothing. It grows in thick hairs and can sometimes be gray, black, brown, or red.

6. Hair algae

Hair algae are all hard to remove from tanks. They often look like wet hair and hang on to different things in the aquarium. They grow so fast due to excess nutrients in the tank or light.

What Causes Algae?

A few things make algae grow in your fish tank, and they’re mostly things you can prevent from happening. The major things that cause algae in your aquarium are: 

1. Nutrient imbalance

When there’s a nutrient imbalance in your tank, you should get ready to receive algae in it. That is what excess or too little nutrients can do. Major factors like food, waste, light in abundance, or lack can cause algae and other organisms to grow.

2. Lighting

Exposing your aquarium to too much light, whether artificial or direct sunlight, can cause algae growth in your fish tank. When you notice algae, one of the first things to do is reduce exposure to light.

3. Waste

The presence of waste from fish and their food can make algae appear in your tank. When the waste becomes too much, and your aquarium’s filter can hardly do anything, algae begins to set in.

4. Irregular water changes

Not regularly changing your tank’s water can make algae grow and bloom in your tank. As an aquarist, this is one thing you should never joke with.

How To Get Rid of Algae In Fish Tank

Thankfully, algae don’t have to take over your tank because you can do something. Knowing how to get rid of algae in a fish tank is something you should know if you want your fish to thrive.

Here are some solutions to try:

1. Introduce algae-eating fish

Introducing algae-eating fish into your tank is one natural way to get rid of algae. Fishes like Siamese flying fox, plecostomus, otocinclus, platys, guppies, mollies, etc., eat algae, so you might want to add them to your tank.

But first, you need to check their compatibility with the current fish breed in your tank so you don’t make any mistakes. You could also introduce some snails or shrimps.

2. Water change and tank maintenance

This is probably the first thing to do when you notice algae. Change the water in your tank and see if they appear again. Also, you need to clean your tank, the plants, substrates, and other decorations in your tank. If algae persist, then you can try other methods.

3. Avoid overfeeding

Excess fish food and waste in the tank can cause algae growth. Therefore, you need to cut the food you give your fish. Also, you need to remove uneaten food from the tank quickly.

4. Avoid direct sunlight

Direct sunlight can make algae grow in your tank. If you place your tank in a location where it gets a little or lots of sunlight during the day, you may need to change the position or prevent the light somehow.

5. Reduce artificial light

Lights in tanks are necessary, but excess is bad for your fish. When you notice algae, you can start by blacking out your tank for a while. This might affect your fish or prevent you from getting a clear view, but the goal is to get rid of algae from your aquarium.

6. Use live plants

Introducing life plants into your aquarium can also help to kill algae in tanks. This is because live plants will take up the light and nutrients these algae are surviving on till they can no longer live. You need to get the right plant, or the algae will take over, and the plants will die.

Here are some to try:

7. Manual removal

Another way to get rid of algae in your fish tank is through manual removal. You can use a sponge or scrub to remove algae hanging onto some surfaces in your tank. You can also use a brush to remove hair algae from your aquarium.

8. Use an algae inhibitor

You can also use chemicals such as algae inhibitors to prevent its growth in your tank. For example, you can use liquid carbon in your fish tank, which serves as a fertilizer for your aquatic plants but can also double as an inhibitor.

Additionally, you can use algaecides to remove algae quickly and completely.

9. Clean plants

If algae grow on your aquatic plants too often, you need to clean them regularly. You can dip the plant in a 5-10% bleach solution for a few minutes, rinse thoroughly and return them to the aquarium.

10. Get a filter

If algae persist in your tank after getting rid of them through different means, the problem could be your aquarium’s filter. Replace it with a diatomic filter and you’ll notice a change.  

How To Prevent Algae From Blooming In A Tank

After getting rid of algae from your tank, you need to ensure they don’t find their way back. Unless, of course, you enjoy getting rid of them often. Preventing algae from your aquarium is pretty easy.

You need to perform occasional water changes at selected times and maintain a clean tank. Also, you need to monitor algae appearances and carry out routine maintenance.

Should You Use Algaecide?

When algae persist, you may consider using algaecide to completely remove them. Sure, you can use it but let it be a short-term solution because it can adversely affect living organisms in your tank.

For example, it can destroy some live plants in your aquarium and it can also kill shrimps, if any, in your tank. However, they’re good for getting rid of stubborn algae in your tanks, and there are a few safe ones you can use.

Lastly, ensure you follow the manufacturer’s instructions when using an algaecide in your tank.


Algae can appear in your tank at any time due to different reasons. Therefore, knowing how to get rid of algae in fish tanks and prevent them is the knowledge that’ll come in handy as an aquarist.

Most importantly, ensure you do routine tank maintenance and water change and examine the water often for any signs. 

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