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How to Remove Algae from Ponds Without Hurting Fish: 8 Tips & Methods

Lindsey Stanton Profile Picture

By Lindsey Stanton

fish pond filled with moss

Algae in a pond can be a massive pain to try to get rid of, but it’s usually necessary to get rid of it. Low levels of algae aren’t a problem most of the time, but large amounts of algae can become dangerous to your aquatic animals, and they can take nutrients from the water that your plants need to grow. Algae is a great source of oxygen during the day, but at night, it often begins to pull large amounts of oxygen from the water, which can suffocate the animals in the pond. Finding ways to get rid of algae safely can be difficult to achieve, so here are the things you need to know about removing algae from your pond without hurting your fish.

aquarium plant dividerThe 8 Tips to Remove Algae from Your Pond

1. Remove the Algae

Algae can be manually removed from the pond with a garden or pond rake. It’s important to be extremely careful to not damage plants, animals, or your pond’s liner when you’re doing this. Removing as much visible algae as possible will make getting it under control and removing what remains much easier.

cleaning pond
Image Credit: pfluegler-photo, Shutterstock

2. Remove Debris from the Water

While you’re raking the pond, go ahead and gently remove debris that has made its way into the pond. This includes leaf litter, grass clippings, and anything else that may be adding nutrients to the water or creating a healthy environment for algae.


3. Add Rooted Plants

Jungle Vallisneria Rooted Plants

The addition of rooted plants to your pond will help decrease the nutrients in the water. If you have fish, they are constantly releasing waste products into the water that plants use for energy. The more healthy, growing plants you have, the more nutrients are pulled from the water. The removal of these nutrients will decrease what the algae can use for energy to grow and reproduce.


4. Add Floating Plants

Floating plants exclusively pull nutrients from the water column, as opposed to rooted plants, which often pull from the water column and the substrate. Floating plants, like water lettuce and water wisteria, don’t just pull nutrients from the water, but they also create shade. Algae needs light to grow, so the more shade you’re able to create in your pond, the less algae will be able to grow.


5. Add Barley Straw

Barley straw is placed near the surface of a pond and as it breaks down, it releases byproducts that help maintain water clarity. Typically, a single small bale treats around 1,000 gallons of water for up to 6 months. Barley straw can be used to prevent or eradicate algae without adding chemical algaecides to the water.

barley straw
Image Credit: bernswaelz, Pixabay

6. Support Beneficial Bacteria Colonization

A healthy pond has healthy levels of beneficial bacteria, which help break down waste products from fish. As waste products are broken down and removed from the water, the algae lose the extra nutrients that would be in the water otherwise. Beneficial bacteria can be purchased in liquid or tablet form, but it will also develop on its own over time, living on surfaces and within the pond’s filtration system.


7. Try a UV Light

Red-eared slider turtles in aquarium tank with UV light and filter
Image credit: TIPAKORN MAKORNSEN, Shutterstock

The addition of an in-line UV light can safely and effectively kill free-floating algae in your pond. This won’t work for algae that is growing on surfaces already, though. UV lights can be purchased independently of other equipment, but many pond pumps also include a built-in UV light.


8. Use Algaecide

Sometimes, chemical algaecides are necessary to quickly eliminate the algae in your pond. If overdosed, these can be dangerous to the health of your aquatic plants and animals, so following instructions carefully is important. Algaecides rapidly kill off algae, which can decrease water oxygen levels to dangerously low levels, so it’s important to ensure that all filtration and aeration is running around the clock when using chemical algaecides. As the algae dies, it will need to be removed from the pond manually.


Our Favorite Products for Algae Control in Ponds

Rating Image Product Details
Winner
Summit Clear-Water Barley Straw Pond Treatment Summit Clear-Water Barley Straw Pond Treatment
  • Safe for all fish, plants and animals
  • Free of harmful or synthetic chemicals
  • Lasts for up to 6 months
  • Second place
    Summit Clear-Water Barley Straw Extract Pond Treatment Summit Clear-Water Barley Straw Extract Pond Treatment
  • Will keep water sparkling and unclouded
  • Will not harm fish, plants or other creatures
  • Suitable for use in aquariums, fountains
  • Third place
    Extreme Max Floating Weed Lake Rake Extreme Max Floating Weed Lake Rake
  • Works in water and on land
  • 50' rope eases water guidance
  • Professional-quality landscaping rake
  • Tetra Pond GreenFree Ultraviolet Pond Clarifier Tetra Pond GreenFree Ultraviolet Pond Clarifier
  • Combats heavy algae blooms in ponds
  • UV bulb that can last for up to 11 months
  • For ponds up to 1,800 gallons
  • API Pond Algaefix Algae Control Solution API Pond Algaefix Algae Control Solution
  • Controls green water algae, string or hair algae
  • Keeps ponds, water gardens and ponds clean
  • Safe for live plants and pond fish
  • 1. Summit Clear-Water Barley Straw Pond Treatment

    Summit Clear-Water Barley Straw Pond Treatment

    Check Price on Chewy

    Pros
    • Safe for all fish, plants and animals
    • Free of harmful or synthetic chemicals
    • Lasts for up to 6 months

     

    Cons
    • Will need many for large ponds

    This two-pack of barley straw bales treats up to 2,000 gallons of pond water. Each bale lasts up to 6 months and can safely eliminate and prevent algae in your pond.


    2. Summit Clear-Water Barley Straw Extract Pond Treatment

    Summit Clear-Water Barley Straw Extract Pond Treatment

    Pros
    • Will keep water sparkling and unclouded
    • Will not harm fish, plants or other creatures
    • Suitable for use in aquariums, fountains
    Cons
    • Treatment has a strong odor

    Barley straw does require some babysitting because the bales won’t work if they sink to the bottom of the pond. Using this barley straw extract can help you get the benefits of barley straw without the extra work.


    3. Extreme Max Floating Weed Lake Rake

    Extreme Max Floating Weed Lake Rake

    Pros
    • Works in water and on land
    • 50′ rope eases water guidance
    • Professional-quality landscaping rake
    Cons
    • Hard it is to drag back because of weight

    This floating weed lake rake is a great option for raking algae from your pond. It’s not too sharp and the floating aspect means that if your rake gets away from you, you won’t be trying to fish it from the bottom of the pond.


    4. Tetra Pond GreenFree Ultraviolet Pond Clarifier

    Tetra Pond GreenFree Ultraviolet Pond Clarifier

    Pros
    • Combats heavy algae blooms in ponds
    • UV bulb that can last for up to 11 months
    • For ponds up to 1,800 gallons
    Cons
    • Hard to see UV light through the window

    This is a fantastic in-line UV pond clarifier. It can be installed in the tubing for your pond’s filtration system, helping to kill the free-floating algae in the water as it runs through the filtration system.


    5. API Pond Algaefix Algae Control Solution

    API Pond Algaefix Algae Control Solution

    Pros
    • Controls green water algae, string or hair algae
    • Keeps ponds, water gardens and ponds clean
    • Safe for live plants and pond fish
    Cons
    • Can not use with freshwater crustaceans

    This chemical algaecide is possibly the best on the market. It’s safe and effective when used properly. Within three days, the algae in your pond should be dead or dying. This can be used as a preventive algaecide as well.


    6. PondCare Microbial Algae Clean

    PondCare Microbial Algae Clean

    Pros
    • Formulated to help remove potentially dangerous debris and organic sludge
    • Registered with the Environmental Protection Agency
    • Available in three sizes
    Cons
    • Algae may grow bak after several applications

    This is a bacterial algaecide, which means that it works to kill the algae in your pond while simultaneously supporting the beneficial bacteria colonies. It is safe for pond life and effective against algae.


    7. Microbe-Lift Algaway 5.4 Pond Water Treatment

    Microbe-Lift Algaway 5.4 Pond Water Treatment

    Pros
    • Eliminate unsightly green water
    • Designed to help control string algae
    • Safe for most pond fish and live ornamental plants
    Cons
    • Not safe for use with snails, shrimp and other crustaceans

    Another great chemical algaecide, this product stops algae growth in your pond and works to kill the existing algae. If used properly, it is safe for pond life.


    8. Microbe-Lift PL Pond & Lagoon Bacteria Water Treatment

    Microbe-Lift PL Pond & Lagoon Bacteria Water Treatment

    Pros
    • Packed with beneficial nonpathogenic bacteria
    • Reduces ammonia, nitrogen, odors, biological waste
    • Improves oxygenation in your pond
    Cons
    • Treatment is not intended to be used with saltwater aquariums

    If your pond needs a beneficial bacteria boost, then this product will help you achieve that. The bacteria in it serves as a bacterial algaecide and a boost to your beneficial bacteria colonies.

    aquarium plant divider

    Conclusion

    Killing and removing the algae from your pond can be a multi-step process. If things have already gotten out of hand, then you’ve got your work cut out for you, but there are a ton of products and methods you can use to kill, remove, and prevent algae in your pond. It’s important to stay on top of things, considering algae prevention and removal to be one aspect of your routine pond care. This will keep your fish safe and will prevent a lot of extra work for you.


    Featured Image Credit: Paula Cobleigh, Shutterstock

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