Is Algae Bad for Betta Fish? Everything You Need to Know

If you are an aquarist, you already know that it is normal for algae to appear in your aquarium. There are many reasons for algae to grow in a fish tank, and their thriving can be a nuisance.

So, is algae bad for betta fish? If you are interested in this topic, let’s read to the end of the article to avoid missing valuable information.

Is Algae Bad for Betta Fish?

Algae are not harmful to all fish

The answer is No. Algae isn’t always a bad thing for aquariums. It’s only when algae growth gets out of control that it becomes a problem.

Overgrowth of algae can create a mess inside your aquarium, yet, biologically, they are harmless. Algae do not harm all fish, including bettas.

Some aquarists and fish keepers even let certain algae grow in their tanks to give them a natural look.

Algae are also beneficial for your aquarium. For example, algae can remove harmful substances from water because they absorb nitrates and phosphates.

Yet, the level of removal of nitrates by the algae is negligible. So you should not consider it as the primary method for removing nitrates from your aquarium.

In addition, some fish are incredibly fond of eating algae, such as snails and bottom feeders, and most of their diet is algae. So you might consider adding these species to your betta tank to increase the abundance.

What Are the Common Causes of Algae in Betta Tanks? 

What causes algae to grow in betta tanks?

Not Enough Cleaning

By cleaning your tank, you can remove all algae buildup and any nutrients they need to grow, such as nitrates and phosphates.

Infrequent Tank Water Changes

Regularly changing your tank water allows you to reduce the risk of algae because it enables you to remove some of the nutrients that algae need to grow.

So we recommend doing a 10 to 20% water change weekly or every two weeks to keep algae growth under control.


Having too many fish in your tank will lead to more waste. Similarly, overfeeding will lead to more leftovers. As we all know, waste and leftovers will release nitrates and phosphates as they decompose, which algae need to thrive.

Too Much Light

Too much light can also cause algae to grow uncontrollably in the tank.

Betta fish feature a circadian rhythm. Hence, as long as you ensure they get six to eight hours of light a day, they will be fine.

How to Remove Algae From Your Betta Tanks?

Removing Algae By Hand

It is one of the easiest ways to remove algae. It doesn’t mean using your hand to scrape them away. Instead, there are various tools to help you remove algae.

You can buy algae scrapers and scrubbers on Amazon easily. If they are not working, you can use a plastic razor to get rid of any stubborn algae. 

Use Hot Water And Bleach

After removing all the algae from your aquarium, you need to clean your decorations. Once your decorations are out of the tank, you need to scrub them in hot water till you have gotten all the algae off.

When dealing with stubborn algae, it is essential to soak your decorations in a bleach solution (95% water and 5% bleach) for half an hour.

Then, clean them thoroughly with water before putting them back into your aquarium. Avoid using bleach solutions with natural decorations like driftwood.

Vacuum The Gravel

Once you have cleaned your tank’s sides and your decorations, it is time to vacuum the gravel.

All the algae that have fallen from your tank’s sides will land there. They will disappear after you vacuum them.

Use Less Light

For the next few weeks, you should limit the light your aquarium can receive.

It is best to ensure it receives light for five to six hours daily. That way, the algae won’t be able to photosynthesize enough to thrive.

Use An Ultraviolet Sterilizer

You can use an ultraviolet sterilizer as a great solution to get the algae off. 

This unit is affordable, ranging from $10 to $30. In addition to removing algae, it is beneficial in getting rid of harmful substances and bacteria in the tank.

The ultraviolet sterilizer will not harm your betta because it mimics the ultraviolet rays in sunlight.


You can also use an algaecide to get the job done. However, we recommend avoiding using it as it can negatively affect other things in your aquarium, especially invertebrates and live plants.


What Eats Algae the Most?

If your aquarium is large enough, consider keeping some algae eaters with your bettas. We recommend using Otocinclus and Plecos catfish for a larger tank. For a smaller tank, you’ll be fine with a couple of snails.

Can I Prevent Green Algae In My Betta Tank?

How to prevent green algae in a betta tank?

There is no way to stop algae completely. However, you can still keep them under control by:

  • Minimizing the amount of light.
  • Keeping algae-eating tank mates.
  • Adding more live plants to the tank.
  • Ensuring you are changing the water.

Does the Algae Disappear on Its Own From My Aquarium?

The answer is No. Instead, algae will grow rapidly under ideal conditions. To remove creation, you need to do the methods that we mentioned.

Can High Chlorine Cause Algae?

Too much chlorine can also cause your tank water to discolor, but no algae can grow in the tank water with high chlorine levels.

Why Can’t I Get Rid of Algae in My Tank?

The cause could be that your tank is getting too much light or too many nutrients in the water.

Wrapping It Up

Is algae bad for betta fish? No, algae growth is not harmful to betta fish in particular and all fish in general.

However, just because algae are not biologically harmful doesn’t mean you shouldn’t get rid of them. You should keep their growth under control to avoid forming a mess in your aquarium.