How To Get Rid Of Algae In A Pond Naturally | Safe For Fish

In this article, we’ll cover a few Home Remedies For Pond Algae that you can use to combat some of the most common types of pond algae you’ll likely see in your pond.

You’ll also learn about the best algae-free backyard pond ideas, ways to control an algae problem in a garden pond, some common types of pond algae, what causes algae to grow, tips to control the algae, and of course, some natural products you can use if you find algae growing in your new pond.

Let’s go

Natural Algae Remover Options That Are Safe For Fish

Types of Pond Algae

1. Blue-Green Algae

There are numerous types of unwanted algae; experts say that blue-green algae are the worst type to grow in your backyard pond.

They can result in harmful algae blooms as well as toxic algae and can appear like pea soup. The term blue-green algae is a class of bacteria named Cyanobacteria.

2. Filamentous String Algae

These algae grow swiftly and affect your pond water ecosystem and appearance. In tiny amounts, filamentous algae growth is not destructive.

However, it is critical to control string algae growth before it becomes unmanageable.

3. Green Pond Algae

These algae are a common type of planktonic algae. They are usually beneficial in tiny amounts, but certain strains or excess growth can be detrimental.

They should be cautiously monitored and controlled.

4. Golden Algae

These are blooms that often have a golden color. They appear on the water surface, mainly in coastal waters, and thrive in temperatures between 65°F to 85°F.

In small amounts, they are not harmful. These algal blooms are toxic to fish but not to other animals or humans.

5. Red Pond Algae

Similar to cyanobacteria, they are not precisely algae but protozoa that typically appear red.

They can be found in nearly every body of water, and blooms are typically a shade of red but may turn green. They prefer warm waters and can be toxic in large quantities.

They are incredibly harmful to fish.

What Causes Algae To Grow In A Pond?


Algae and cyanobacteria thrive on nutrients.

The nutrient enrichment of water bodies is considered a significant factor in their growth. The primary nutrients which contribute to how much algae grows are phosphorus and nitrogen.

Water Temperature

Blue-green algal blooms typically develop during the early spring. The water during this season is high, and there is increased light. Their growth is sustained during the warm months of the year.

Temperatures above 25°C create an optimal environment for their development.

At these temperatures, the blue-green algae have a competitive advantage over other types of algae, which can only thrive in lower temperatures.


The populations of blue-green algae are diminished when they are exposed to long periods of extreme light intensity. However, they have optimal growth when exposed to high light intensities intermittently.

These conditions are met beneath the water surface, where the light environment is changeable.

What Kills Algae Naturally? Try These To Get Rid Of Pond Algae

So how do I control algae in pond?

You can get rid of algae naturally using live plants, avoid overfeeding, cleaning the surface water and keeping fish that will eat algae among other things.

Below we go into more detail about each option.

Use Live Pond Plants

Aquatic plants like water lilies help break down fish waste accumulated in the water that allows the algae to thrive. The algae will also require some sunshine, similar to fish, so putting some flowers and grass cuts on your pond mitigates the source of algae enrichment.

Fragrant water plants are beautiful and have a wonderful scent. They provide adequate shade and hiding spots for fish to keep them safe from predators and can further fight bacterial growth by contributing to the nutrient cycle of the pond’s ecosystem.

Avoid Overfeeding

It’s best if you do not overfeed fish since leftover food may rot. If your pond has fish, you should only feed enough food that they can consume in five minutes.

If you provide large amounts, excess food will only drift to the bottom and decay, which can be a catalyst for algae growth.

Use A Skimmer To Remove Surface Algae

Get rid of algae from the surface of your pond by utilizing a skimmer or algae net. It is the most effortless way to clean the top of the pond.

Use a skimmer or net to skim the pond’s surface, pull algae, and remove it. It may take a while, but it will give you fast results.

Add Barley Straw

Barley straw is an organic way to mitigate algae.

Once in contact with water, the straw starts breaking down. It releases peroxides into the water, which can fight off algae.

Barley straw is available in mini bales or as a concentrated barley straw liquid extract. It is a natural way of fighting algae chemically. If you want faster results, you must opt for the liquid form since the straw can take time to take effect.

Keep Fish That Will Eat Pond Algae

Koi Fish In Pond To Help Control Algae

Certain fish species can help in cleaning up a pond by consuming algae. Algae is safe for fish to eat. Algae can live and grow in stagnant water and can swiftly take over an entire pond if left unmitigated. You must add the optimum amounts of pond cleaning fish to keep algae to a minimum.

Homemade Algaecide For Ponds And Fountains

Homemade bleach combined with fountain water can be an efficient homemade algaecide when no plants or other aquatic life live in the fountain or the pond.

But bleach may not be ideal since it can be harmful to the material of a fountain.

It is also potentially harmful to animals drinking from the fountain and kids playing in the water. Because of this, an alternative DIY algaecide is to add oxygen bleach to the water, which has zero toxic ingredients, unlike chlorine bleach. If you utilize powdered oxygen bleach, you must dissolve it entirely in water before adding it to the pond or fountain.

Using Hydrogen Peroxide In Your Pond

You must first measure your pond to determine its volume. You must know its width, length, and depth too. Combine ½ cup of 3% hydrogen peroxide with 100 gallons of pond water. It is crucial to pour the peroxide into the pond far from the fish and stir the water around to mix it in.

You must note that hydrogen peroxide can harm fish gills, so never pour it directly on fish. Never use more than the recommended amount because it can result in algae dying off too quickly, leading to an ammonia spike, which is extremely dangerous to fish. The peroxide will take effect within several minutes, and the increased oxygen will last for several hours.

Why You Should Get Rid Of Pond Algae Right Away

Although algae are beneficial to the ecosystem of a fish pond, when their growth gets out of control, it can result in problems. Some species of algae can release toxins, but the most common reason fish die related to algae is the depletion of oxygen levels.

Tips to Remove Pond Algae Naturally


If you have a small pond, the first step is controlling algae manually. You can utilize a pond or garden rake to get rid of surface algae. However, if you have a large pond, you could opt for a chemical algaecide.

There are quality algaecides available that will provide almost immediate solutions for algae situations out of control.

It is critical to apply it properly to your pond. If you are unsure of how to correctly apply it, schedule a consultation with a pond expert. Proper use of algaecides is crucial in keeping the fish safe as well as removing harmful bacteria.

Plant And Install

Another step is to build your arsenal in defending against unmitigated algae. You can use natural or artificial methods. But in many cases, you will need both.

Natural solutions include placing plants that cover up to 50 to 70% of your pond. If you have a large pond, you need to utilize a pond aeration system.

Aeration and beneficial bacteria mitigate nutrients already present in the pond, but this process will take some time. These are critical if you want to control invasive algae in the long term.


The final step is to monitor and maintain the pond. If you have followed the steps above, you should be successful in eradicating unwanted algae. But maintenance is required to prevent future outbreaks.

How To Remove Algae From A Pond Without Harming Fish?

You can get rid of algae in your pond without harming fish by utilizing a pond or garden rake to get rid of as much surface algae as possible.

But if your pond is large, you can begin by using a chemical algaecide. There are numerous quality algaecides available that will provide fast relief when correctly applied to your pond.

Recommended Natural Algae Control Products


Copper is typically the first intervention pond owners turn to when they want to control algae growth. The most popular form is granular copper sulfate.

It is efficient and is a comprehensive range controller of planktonic and filamentous algae. Because of this, it is highly used. Another type is liquid chelated copper, which controls a broad spectrum of algae, including bottom attached types of algae.


This product is a potent herbicide as well as algaecide typically used in natural ponds. It is safe to use and can be applied to control every type of algae in ponds. It is best to combine this with aeration methods to combat the adverse effects of the algae die-off.


Granular-based peroxides are fast-acting contact algaecides for algae of the string type. It acts fast and bubbles as it oxidizes, as compared to medical-grade hydrogen peroxide.

Its byproduct is oxygen, and it is safe for fish at specific dosages. But it would be best if you took the filaments and cellulose out of the water, or they might settle at the bottom of the pond.

It is costlier than some other products, but it is fantastic for spot treatment and does not have harmful residues.

The application rate varies, so it is crucial to follow the instructions on the label. As an added benefit, it works at cleaning algae in other areas such as tanks, sidewalks, and even roofs. This method of control also works well in small applications such as in gardens.

Pond Dye

Dyes are available in either blue or black, as well as powder or liquid. They dye the clear water and act to shade and mitigate sunlight penetration that feeds the growth of algae.

As an added benefit, tinting the water blue or black keeps predatory birds from preying on the fish in your pond because they cannot see the fish. Dyes in combination with aeration also work optimally because it helps mix the water to disperse the dye evenly.

Bacteria And Enzymes

This approach is non-chemical and involves utilizing living organisms to feed off the excess nutrients that plants otherwise access. These are typically naturally occurring bacteria and enzymes that are concentrated. They help in improving water quality.

It is a rapidly biodegradable sludge that mitigates suspended particles, particulate matter, solids and manages odor if used correctly in the optimal blend for the pond.

Ultraviolet Sterilizers

This product typically works by utilizing a wavelength of light that will help to get rid of planktonic algae. It is highly efficient for green water but has little effect on certain types of algae.

It does not pass through the unit to be exposed to the light. It should only be viewed as a reasonably practical approach for small ponds and gardens. However, it is not an effective way when used for larger ponds because of the high cost of large-scale units.

Ultrasonic Sound Waves

The basic premise behind these units is pretty straightforward. They utilize ultrasonic resonance ways to get rid of algae. Since the submerged transducer gives off ultrasonic waves, it shocks the algae and eliminates them by tearing the sac, allowing them to float.

This product type should not be harmful to your fish. But the problem with this approach is that it is costly, and results are not consistent and can be marginally successful. Every pond should be considered a separate organism with varying water quality. The unit should be sized for those unique conditions.

Key Takeaways About Pond Algae Control

When it comes to algae, control is critical to strive for optimum balance.

Every pond will have algae and will never be free of it. But in a balanced ecosystem, algae must be kept in check.

Understanding algae growth is a good start in following appropriate treatments for the type of algae present in your pond. Utilizing UV clarifiers, water treatments, and other algae eliminators are efficient methods for treating and mitigating algae proliferation.

However, don’t ignore what mother nature provides and add aquatic plants, which should be part of a long-term solution.


How do I get rid of algae in my pond without harming fish?

You can get rid of algae in your pond without harming your fish by using UV Light. This will remove any algae particles that are suspended in the water column. As this process occurs your water will change from green to brown to clear.

How do I reduce algae in my pond naturally?

One of the best ways to reduce algae in your pond naturally is to use floating plants. Plant like lilies will block out and reduce the direct sun and help reduce the amount of algae. 

What naturally kills algae?

Another natural way to kill algae is by using some baking soda. Bicarbonate, which is the active ingredient will help kill algae. Once dead you can remove the algae from your pond. You can use a brush or spray bottle to apply the baking soda to the algae.


Jack Dempsey