Why Is My New Pond Water Turning Green? {6 Ways To Clear It Up}

Does it bother you when your pond water looks murky? Why is my new pond water turning green?

Try these 4 ways clear up sludge and muck and 6 tips to clear pond water below.

In this article, we’ll find out why this happened and how to clear up your pond water.

Why Does New Pond Water Turn Green?

Algae is the top reason why pond water turns green. The top 4 reasons are as follows:

  1. algae
  2. lack of plants
  3. insufficient aeration of oxygen
  4. overcrowding of fish producing too much waste

 Your new pond water turned green, but we can fix that. Read on to find out how. 

What is Causing Green Pond Water?

The pond itself has an imbalance of nutrients with nitrates and phosphate levels soaring and algae blooming because of it. If your pond contains sludge and muck on the bottom, you’ve got yourself a poor chance of maintaining a clean pond right from the start.

Look out for the culprits that cause this sludge and muck:

  • dead algae
  • fish waste
  • grass clipping
  • leaves

When these perpetrators decompose, you’re left with excess nutrients that helps algae thrive. This will turn your new pond water green in no time at all.

Does My Pond Need More Oxygen?

Yes. Pond water needs enough oxygen to battle the gases that are developing from excess nutrients from waste and dead organic matter on the bottom of the pond. There are two popular ways to quickly increase the oxygen levels in your new pond:

  1. More plants
  2. Aeration

1. Plants

Plants provide oxygen while devouring the nitrates and phosphates by stealing them away from the algae. Your plants will win and the algae will starve. The oxygen balance will restore itself at the same time, but you can add more of a punch to your pond by aerating it.

2. Aeration

Aerating your pond increases the surface agitation and allows for oxygen to move freely. You can aerate a pond in multiple ways:

  • Waterfall
  • Fountain
  • Filter
  • Air Pump
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How Can I Clear Green Pond Water?

Now that we know we that green pond water can be eradicated, let’s get a little dirty at first to clean up and follow maintenance procedures to prevent it from turning green again.

Here are your 6 tips to help clear your new pond water:

6 Tips To Clear Pond Water

  1. Clean up the sludge
  2. No overfeeding or overstocking fish
  3. More shade
  4. Beneficial Bacteria
  5. Aeration 
  6. Lots of plants

How Do I Clean The Sludge & Muck In My New Pond?

Try these 4 ways to clean sludge and muck in your new pond.

  1. Long handled net
  2. Liquid solutions
  3. Pond Skimmer
  4. Bottom Drain

Try to use a long net or a pond vacuum to help remove the sludge at the bottom of the pond. Once you get the hang of it, you should continue this practice at least once a season.

You’re doing this to remove:

  • debris
  • organic matter
  • dead plants
  • fish waste

Remove these food sources and it’s goodbye green algae!

There are liquid solutions that can help as well. They are sold on the market as Sludge & Muck Removers. The muck is converted to nitrogen and fizzes its way out of your pond.

Pond skimmers and bottom drains are also great suggestions for the next level enthusiast to really invest into the cleanliness of the pond. If this is your hobby, consider going all the way with a skimmer or bottom drain.

Am I Overfeeding My Fish In My Pond?

The more you feed your fish, the more waste they will produce. The waste produces gases that algae thrives on. Your pond’s worst enemies are:

  • Ammonia
  • phosphates
  • nitrates 

Watch your fish eating the food you have thrown into the pond. If they aren’t consuming it within 15-30 seconds, scoop it back up. Don’t let leftover food sink to the bottom of the pond.

Do I Have Too Many Fish In My Pond?

Too many fish will cause overcrowding and stress. This is not today’s problem with the green pond water, but tomorrow’s issue will be that your fish will get sick or float lifelessly at the surface of your pond.

Let’s start by stocking fewer fish until the pond stays clean and clear for the season. Get used to the habit of maintaining your pond by cleaning it and not overfeeding your fish.

Think about 1 inch of fish per gallon of water. Try to not follow that rule exactly and stay well underneath that protocol to maintain a pond that isn’t overstocked.

How Much Shade Should I Have For My Pond?

Algae thrives off sunshine just like any other plant. If your pond is placed in an area without any shade, there are still some ways to create shade within the pond itself.

Look into placing floating plants on the surface of the pond to reduce the amount of sunlight that infiltrates into the pond which promotes the growth of algae.

Here’s a list of floating plants to provide shade:

  • Water lilies
  • Solepsis
  • Water hyacinth
  • Water lettuce
  • Marsh marigold
  • Water mint
  • Aponogeton distachyos 
  • Anacharis 
  • Curly pondweed

Do I Need Beneficial Bacteria For My New Pond?

Yes. Beneficial bacteria is a great way to combat the imbalance of nitrates and phosphates. They consume:

  • algae particles
  • fish waste
  • dead leaves
  • organic matter

Beneficial bacteria is sold out of a bottle under various names. They bind together in the pond and do a great job of gobbling up algae bits or their sources of food.

How Do I Aerate My Pond?

Aerate your pond to add more oxygen circulation. This will help fight algae buildup and allow for beneficial bacteria to break down.

The following aeration devices will help get the job done:

  • Waterfall
  • Fountain
  • Filter
  • Air Pump

Also consider a UV lamp or a filter that comes with ultraviolet light to fight algae that causes pond water to turn green.


You can win the battle against green pond water.

  1. Clean up the sludge.
  2. Don’t overfeed or overstock fish
  3. Provide more exterior shade or add floating plants to shade the pond from within.
  4. Beneficial bacteria eats up algae particles or organic matter that causes green water.
  5. Aeration through filters and air pumps provide more oxygen alongside the addition of more plants to fight the nitrates and phosphates.


We believe you can clear up your pond’s water soon and we’re glad to help out with any pond related questions that you may have in the future. See you again soon!

Brian Arial

Brian Arial has kept fish for leisure and worked with fish stores for most of his life. He enjoys writing and caring for aquariums and ponds.