7 Ways to Naturally Get Rid of Algae in a Fish Tank

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There’s nothing wrong with a little algae in your fish tank. In fact, it can sometimes be beneficial to your fish and give your tank a more authentic feel. However, too much algae can cause problems and doesn’t look to great either. There are chemicals available for killing algae, but I strongly recommend avoiding those. Instead, here are seven natural ways you can get rid of algae in your fish tank.

Just like plants, algae thrives on nutrients and light. The key to getting rid of algae naturally is to limit the amount of light and nutrients they have access to. The most important things are to keep your tank out of direct sunlight, limit the amount of artificial light, and regularly change the tanks water.

Why Choose Natural Methods?

There are chemicals that you can buy that kill algae, and it’s often tempting to go down this route because it seems a lot more convenient. The problem is, these chemicals might kill algae, but they are not good for your fish either. I’ve come across quite a few reports of fish dying or almost dying after chemicals were used to get rid of algae. And these chemicals are supposedly designed for use in a fish tank. As long as you keep it under control (and the steps in this guide should help you with that), algae is unlikely to become such a problem that you have to resort to chemicals.

What Causes Algae to Grow?

Although not technically plants, algae is very similar and grows in a similar way. Nutrients and light are the main factors needed for it to grow. Most of the methods in this article are focused on reducing the amount of nutrients and light to starve the algae and stop it in its tracks.

How to Get Rid of Algae Naturally

Below you can find 7 natural ways for getting rid of algae from your fish tank. Some of these will require some work, but there are also some simple things like reducing the amount of food and light that can really make a big difference.

1. Reduce Light

Just like plants, algae use photosynthesis to create their own food. Reducing light – both artificial and sunlight – is a great way to get rid of algae. Always try to avoid positioning your fish tank in direct sunlight. You’re begging the algae to grow if you do, and the drastic changes in water temperature as the sun comes and goes isn’t good for your fish either. For artificial lighting, try and limit it to no longer than eight hours per day. The best way to control this is by using an electronic timer. I highly recommend a timer that comes with a battery as a back up like the Hydrofarm TM01715D (click to check price on Amazon). The Hydrofarm has great reviews and isn’t too expensive either.

2. Reduce Food

It is common for fish owners to overfeed their fish. This causes an increase in phosphate levels in the tank and promotes algae growth. Of course, you don’t want to starve your fish, but for many people, reducing the amount you feed them can help to get rid of algae. So, how do you know if you’re overfeeding? Well, after you have fed your fish, if there is any food left over after five minutes, you should reduce the amount you are feeding them until they can clear it up within five minutes. Any uneaten food should quickly be removed with a net or pipette.

3. Change Your Water Frequently

Algae thrives on nutrients, and if you don’t change your water regularly it can contain a lot of nutrients. You should aim to change 10 – 15% of the water weekly. You can also use this as an opportunity to vacuum and clean the gravel.

4. Introduce Algae Eating Creatures

There are many fish and creatures that absolutely love to eat algae. Introducing a few of these creatures into your tank is a great way to keep algae under control. However, you do need to keep in mind that this won’t outright fix the problem and only cover it up. The root cause of the algae will be an imbalance of the nutrients in your water, and you really need to address this. But algae eaters will definitely help and it’s a fun method too!

5. Keep More Plants

Plants thrive on many of the same nutrients as algae. Introducing more plants into your fish tank, especially fast growing varieties, will starve the algae and help to prevent it from growing. Floating plants are even better because they will also block out much of the light that the algae needs to grow.

6. Be Careful Not to Introduce It

Adding live plants to your aquarium is a great idea for reducing algae, but be careful the plants you introduce don’t already have algae on them. If you notice algae on them, you can follow our guide to removing algae from aquarium plants.

7. Keep Your Tank Clean

As soon as you see algae starting to grow in your tank, clean it before it has a chance to grow and become a bigger problem. To clean the glass, you can use a credit card to scrape away the algae, or if you don’t want to get your hands dirty you can use a magnetic cleaner like the FL!PPER cleaner (click to check price on Amazon). Whenever you do a water change, you can use the opportunity to vacuum and clean the gravel. You’re also going to want to remove rocks and ornaments and scrub away any algae on them. Plants can be a little trickier, but you can find our guide on how to clean them here.

Algae Isn’t All Bad!

Having too much algae in your fish tank definitely isn’t good. For starters, it doesn’t exactly make your tank look appealing. But also, if you have live plants, it will compete with them for light and nutrients, and this can be detrimental to your plants. However, as long as the algae isn’t out of control, it won’t harm your fish, and many fish actually love to eat it. The key is to keep on top of it to prevent it from getting out of control.

How Do I Know If I Have Too Much Algae?

It isn’t like there’s a specific point at which the algae becomes too much, but if you’re reading this article, the chances are your tank is starting to look a bit gross. If this is the case, then you could definitely benefit from following these methods to reduce it. Even if the algae in your tank isn’t that bad, these methods are still a good idea to prevent algae from becoming a problem in the future.


If you take on board the seven methods in this guide, you should be well on your way to a relatively algae-free tank. Remember, algae is natural in a fish tank so don’t worry too much if there’s a little bit here and there. But even if you don’t have a significant problem with algae, it’s still worth following the methods in this guide to prevent if from becoming a problem in the future.

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