How to Get Rid of Algae in a Fish Tank

Algae Control – How to Get Rid of Algae in Your Fish Tank

If you are struggling on how to get rid of algae in a fish tank this article is for you.
Let’s start understanding more about algae.
There are two types of algae, the good kind, and the bad kind.

hot to get rid of algae in your fish tank

The good algae are the one that grow naturally and not in excess in your aquarium, the one that can easily be controlled with quick and easy solutions.

The bad algae are the ones that you have to worry about and attack more aggressively.
The bad type will overpower your aquarium and leave you with murky water and an unclean look to your tank.

You need to know that your aquarium
will probably never be completely algae free.
Some algae are normal and shouldn’t be so much of a concern.

What you do want to do is keep the bad algae under control and make sure that they don't become a problem.
Keep reading to know the preventative measures and also the solutions like algae eaters and other options to help you keep your fish tank free of the algae that can potentially damage the aquarium environment.

What are the Most Common types of algae

Here are the most common aquarium algae types that you may encounter in your fish tank.

Brown Algae

Brown algae in a fish tank are quite common.
Until the water stabilizes, there are fluctuations happening in the water that is the perfect environment for these guys to grow.
This brown spot algae will grow on decorations, on plants, and even on the glass.

Green Hair Algae

The green hair algae are the most common algae that grow in aquariums.
It is light green and can be in different shapes, like spots or have a hairy appearance.
They are quite easy to get rid of but can return just as quick.

Black Red / Brush Algae

The black red algae will grow on the leaf edges of your plants that are the slowest growing.
They develop in clumps or patches varying from black to red.

Blue Green Algae

The blue green algae are not really algae, they are actually bacteria, but can be treated the same way as algae in your tank.
They are a slimy type mossy substance that can quickly overtake the substrate, especially where the glass meets the gravel.
It also has a bad smell to them.

Green Spot Algae

The green spot algae will grow on the glass and plant leaves and form green spots that are difficult to remove.

Stag Horn Algae

The stag horn algae grows like antlers in stands.

Green Water

You will want to prevent green water, as this is a major problem to face.
As the word suggests, your water becomes murky and develops a green tint.
This creates an unsafe environment for your fish to live in as well as being an eyesore.

Check out this article if you want to know more about these common types of algae.

What are the sources that feed the algae?


Light is the number one source of energy for algae.
Without light, it will not grow.
Being that we enjoy to see our fish in our aquariums and seeing that they also need some form of light to live, we will unequivocally have a source of light in our aquariums.
Light needs to be monitored and timed in order to keep the algae from developing.
More on this later in the article.

Water Temperature

Warm water is a breeding ground for algae to set up and flourish.
If you have a freshwater tank and don’t live in a tropical location, you most probably have a water heater in your aquarium.
The amount of heat provided can give ammunition to the algae to grow.


Algae feed on nutrients like food waste, fish waste, decaying debris and other toxic detritus in the water.
If you overfeed your fish or overstock your tank, chances are you will have to deal with an excess of nutrients in your tank which will, in turn, lead to potential algae growth.

PH level

Low or high pH levels in your tank may affect the growth of algae.
High or low alkaline and acidic levels is an unhealthy environment for your fish and also will promote the algae to form and spread.
This article will provide you more insights on how you can control the pH level in your aquarium.

How to Keep Algae Under Control

There are things you can do to prevent algae from growing in your tank.
Let’s take a look at a few things that you can easily do to try to avoid it from forming.

Algae Eaters

Some fish and invertebrates thrive on the algae that you find so unattractive in your aquarium.
Adding a few of these algae eaters will help in controlling the growth.

There are many varieties of fish and invertebrates that dine on the stuff in your tank, you will have to research the types that are suitable for your tank.

Depending if you already have a set-up tank that has communities of fish already established, you will have to make sure that the new additions will be compatible.
The most common ones that we see on the market today are the plecos.
There are several types of plecos, some that even grow very large.
Keep in mind that they are not miracle workers and some algae may grow faster than the little chompers can eat, so there still may have to be some other options to consider.

This is actually a fun way to help with the algae fruition as you get to have new aquatic friends to look at.
Just make sure to not overstock your tank and choose the right size algae eating creatures necessary for your tank size.
If you want to read more on algae eaters check out our post here.


Algae need light to proliferate.
You may want to reconsider your lighting source and the amount of time that the aquarium is exposed to light every day.
Weakening the light source and diminishing the number of hours you illuminate your tank may help to prevent the development of algae.

Purchasing a timer is usually useful for this situation as you won’t have to worry about turning on and off the lights.
The Zoo Med AquaSun Aquarium Timer can easily do the job and is quite inexpensive. Check it out on Amazon here.
Try to mimic a day/night cycle in your tank.
Lights should be on for about 6-10 hours for a non-planted aquarium and 10-14 for a tank with plants.

Also, change your light every year, as the diminished quality of your light bulb may actually increase the chances of algae growth on your tank.
Check out our post on LED lights if you want to know more.


Increasing the CO2 in your aquarium will help to avoid the formation of algae and will also help keep your fish happy.
Oxygen starves algae so that they can’t proliferate.
Using aeration devices in your tank such as air pumps, airstones and bubble disks will increase the health of the water and add a touch of fun to the tank.

Fish Feeding

One of the main factors that encourage algae growth in your tank is food waste.
This is by far the most common fishkeeping mistakes a new aquarist can make.
We all like the feeding time and watching our fish become lively and active and we are inclined to give more than they really need because we like to keep our fish happy.
But there are times when we tend to overfeed out fish.

This is easily remedied by feeding your fish only what is necessary.
This is easier said than done. Observe your fish as they eat at feeding times.
If you notice that some food is left over after a few minutes, that probably means that you are giving them too much.

This will be a trial and error period and will change as you add or remove fish from your tank.
The food that is not consumed by your fish usually sinks to the substrate and creates a perfect toxic element for the algae to grow on.
Nitrate levels rise and algae get food to grow.

An option is to use automatic feeders. They are a good assistance to time and dose the food. Check out here our post on feeders to learn more on how they work and what you can find on the market.

Working Filter

Obviously, to keep your water clean and free from toxins, you need to provide a good filtration system in your tank.
We have an article that will tell you everything you need to know about aquarium filters here.

A 3-stage filter system is the most common filtration system available to aquarists today and they do an excellent job of taking care of everything undesirable in your tank.
Having a proper filter that functions suitably for your size aquarium will ensure that toxicity levels remain low, thus diminishing the probability of algae formation.
Also, make sure to clean and change your filter media when necessary.

How to Get Rid of Algae in Your Fish Tank

There are several ways to tackle the removal of algae in your aquarium once it has settled in. Let’s take a look at the different options.

Manual Scraping

This is by far the most time-consuming of all methods available, but one of the most efficient.
You will get down and dirty with your aquarium and clean all elements and scrape windows, gravel, and decorations free from the algae.
Things you may need in order to manually scrape the inside of your aquarium:











Start with the inside glass of the aquarium, and then move to the decorations and gravel.
Next, you will clean the outside of the tank and then all exterior elements. Lastly, you will want to clean your filter.

Algae scrapers or pads

There are a lot of different types of algae scrapers out on the market today.
Better to use a reliable aquarium scraper or pad and not a household sponge found in any old store.
Store sponges may contain soaps or other chemicals that could harm your fish.
Some have handles, and the prices vary greatly.

Choose one that you think you will be comfortable with and that meets your immediate algae fighting needs and also your budget.
You will wash the inside glass (or acrylic) of your tank carefully to rid it of all visible algae.
We have both used this stainless scraper and this double sided sponge and they did the job very well. You can check them out on Amazon.

There are some magnetic scrapers that you can try if you want to minimize your hand-in-your-tank time.
These work well but are not like a good old hand scrubbing.
The Mag Float or the Kedsum Magnetic Cleaner are good picks available on Amazon.

Razor Blade

If there are some stubborn algae that are stuck on the glass and will not come off with the regular algae scraper rubbing, use a razor blade to scrape it off.
Be careful to use a plastic one if you own an acrylic tank because the metal one may scratch the surface of your aquarium.

Clean Decorations

After the glass is clean of all algae, you will attack the decorations inside your tank.
Remove all rocks, artificial plants, or decorations form the tank that has algae growing on them.
Use your scraper or pad to clean the algae off the decorations and pace them back into the tank when they are rid of the visible algae.


If you can’t get all the algae off with the scrubbing, you may have to resort to bleaching the accessories.
Prepare a bleach soak that consists of 10% bleach in a specified amount of water.
You will soak the items for about 15 minutes and then rinse them off very well under running water and let them out to dry before returning them to their habitat.
There is a debate as to whether bleach is a good item to use in any aquarium activity, especially cleaning of accessories and inside elements.
Yes, you can use bleach so long as you dilute and don’t mix it with any other chemicals.

Water Syphon

You will want to clean the gravel at the bottom of your tank next.
There are different types of syphon brands on the market, so purchase the one that fits your needs and budget.
They all basically work by syphoning the gravel and all the debris included, up into a chamber and then retrieving the dirty water out into the sink or into a container.
Make sure to cover the complete bottom of the tank and syphon gravel until water is almost clear.
The Terapump Aquarium Cleaner is a good option for the bucks. Check it out on Amazon

Aquarium Lime Remover or Glass Cleaner

After you have cleaned the inside of the tank, the decorations and the gravel, and removed algae as best you can, you will have to clean the exterior of the tank and all the elements.
Scrub the outside glass, the filter, the hood, and the light with a cleaner that is designated for aquariums.
Don’t use a regular glass cleaner because these contain harmful ingredients that could harm your fish.
Most of them contain ammonia and this can be lethal for your fish friends.
If you go for a glass cleaner we suggest the Seachem Prime that works for salt and fresh water tanks and is available on Amazon.

Water Changes

Frequent and regular partial water changes are a must for any aquarium hobbyist, you simply cannot avoid this chore.
When encountering an algae problem, this is especially important.

You will want to change about 30% of the water and replace it with fresh, clean water.
It’s not a good idea to take more water out because you will remove the good bacteria that has been working to clean your water.
Regular maintenance is required when keeping an aquarium, bit a little more work may be needed when encountering a specific problem like algae proliferation.


Algaecides are another option to getting rid of algae in your tank.
These are chemicals that work to suffocate or destroy the algae that are present in your tank.
You will maybe want to use this alternative as a last resort and if you do, then it cannot be performed too many times.
These come in different types like liquids, powders, or tablets.
Keep in mind that algaecide will probably also affect your living plants and invertebrates,
It’s an easy quick solution but other things should be done as well to keep algae from coming back.

Ultraviolet Sterilizers

Adding a UV sterilizer to your tank will help to diminish and to keep away the unwanted algae from your water.
The UV sterilizer can even kill off the smallest of algae blooms.
The unit targets the unwelcome substance and is not harmful in any way to your fish or other inhabitants of your aquarium. This is always a good addition to any aquarium.
There are several on the market at different price levels, such as the Green Killing Machine or the submersible Aqua UV Sterilizer that are real good choices. Check them out on Amazon.

Remember that after ridding your tank of the ugly nuisance that is algae, you will have to keep vigilant to avoid another outbreak.
Keeping some algae eating fish and invertebrates, making sure not to overfeed your fish, and keeping regular maintenance on your filter will provide adequate algae stopping factors to your aquarist hobby.


The algae problem is often times the number one reason that beginner aquarists quit the hobby.
Don’t become a statistic and make sure that this doesn’t happen to you by being well informed and well prepared just in the case that you do face an algae outbreak.
There is no need to panic and there are preventative measures and solutions to your algae concerns, so keep on fishkeeping!

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Algae Control - How to Get Rid of Algae in Your Fish Tank