How Often Should I Add Beneficial Bacteria to My Pond? {Why You Need It}

I was wondering what adding beneficial bacteria could do for my pond? How often should I add beneficial bacteria to my pond?

Beneficial bacteria are nature’s clean up crew. Not only does the bacteria clear up the water by breaking down the negative organic matter in the pond, but it also improves the health of the fish and plants living in it.

In this article, I’ll tell you all about what beneficial pond bacteria does and how it could help clean your pond.

How Often Should I Add Beneficial Bacteria to My Pond?

For the majority of the year, I advise applying beneficial bacteria to your pond once a week to maintain ideal water quality and clarity.

  • The microorganisms that break down decaying organic matter in lakes and ponds are known as beneficial bacteria.
  • There are many distinct kinds of bacteria, and each one breaks down chemical substances in a different way.
  • Organic molecules are swiftly broken down by aerobic bacteria using oxygen.

Beneficial Bacteria to My Pond

What Are the Best Beneficial Bacteria for Ponds?

The beneficial bacteria in your pond are called nitrifying bacteria. The nitrogen is what breaks down all the pond gunk and debris. With all of the options of nitrifying bacteria on the market, it can become confusing to find the best fit for your pond.

Because there are so many variation choices, for example organic or synthetic and liquid or powder, you might be confused. While your shopping, here’s what to look for to find the best beneficial bacteria:

  1. Made from pure concentrated bacteria, whether it’s organic or synthetic.
  2. Has no additives, with the exception of healthy nutrients like vitamin B.
  3. Safe for all animal life like the fish, and other animals that live in or come by to drink the pond water.
  4. Made to completely dissolve in the water without any film or residue.

The liquid forms will always dissolve, but there are many dissolving powders as well.

Can You Put Too Much Beneficial Bacteria in Your Pond?

Yes. When there are too many helpful bacteria in your pond, they begin to struggle and compete for resources rather than:

  • developing
  • prospering
  • reproducing

Because the stronger competitors are consuming all of the debris, the weaker bacteria perish. This causes the bacteria population to decline.

As a pond owner, I have to go out and buy additional bacteria to restore it. It is therefore simpler to maintain the populations of helpful bacteria rather than overdo it with them.

Does Too Much Beneficial Bacteria Harm Fish?

Yes. Normally, having an excess of good bacteria in your pond is harmless for the plants and the fish. However, your fish may be in serious difficulty if your pond has a lot of organic buildup together with a lot of helpful bacteria and insufficient aeration.

Your fish are in risk because they require oxygen to exist, and while those bacteria are competing for food, they are depleting the oxygen in the water.

Advantages of Beneficial Bacteria for Ponds

When you use beneficial bacteria in your pond, it works to naturally reduce harmful dead matter. Bacteria break down the debris in your pond like scum, algae, and other decaying materials using the nitrogen they produce.

Adding beneficial bacteria to your pond can also improve the health of the fish and anything else that comes by to drink the water. Like probiotics in humans, these beneficial bacteria improve digestion and other functions in the fish and other animal life.

Some other benefits include:

  • Adding nutrients to your pond to help your fish.
  • Decreases slime coating on some fish.
  • Reducing the time spent cleaning your pond.
  • Increasing nitrogen level, which prevents algae.
YouTube video

How Do You Grow Beneficial Bacteria in A Pond?

Adding beneficial bacteria to your pond, also called seeding, can be as simple as putting a healthy dose of fresh and clean water into your pond.

There are multiple ways of promoting beneficial bacteria in your pond. You can add some new water to the pond, but if you don’t have that option, here’s what you can do instead:

  • Give your pond a healthy dose of water from another pond.
  • Adding extra beneficial bacteria products to supplement bacteria levels.
  • Having unchlorinated pond water.
  • Adding rocks and other places for bacteria to colonize.
  • Aerating the pond water.
  • Limit the bad organic material like algae.

How Long Does Beneficial Bacteria Take to Grow?

Typically, a colony of new bacteria will take up to six weeks to finally reach the stage where they start to produce the nitrogen that they’re so beneficial for. Of course, a smaller pond will take less time to produce healthy bacteria.

Each nitrifying bacterium grows within 15 hours. When they reach full growth, they start producing the nitrogen that breaks down all of the organic matter that you don’t want in your pond. This whole life cycle lasts for a month or so.

When you seed your pond, depending on the size and the current state of the pond, you can expect a healthy population of bacteria in even less time.  You can easily buy a starter kit for beneficial bacteria at your local pond supply or pet store.

YouTube video

What Eats Bacteria in A Pond?

While bacteria help to “eat up” a lot by breaking it down, there are also things that eat the bacteria in your pond. They’re even eaten by bigger animals because they make homes in their food.

Simply put, bacteria play their part in the food chain, right at the bottom. They’re eaten by bigger micro-organisms like:

  • zoo-flagellates
  • ciliates

Bacteria are drawn to the algae blooms and other plant matter in your pond, which is the main food source for ducks and turtles. This means that they’re ingesting the bacteria hidden in the aquatic plant life without even knowing it.

How Often Should I Do A Water Change on My Pond?

Farm ponds that are naturally occurring or spring-fed don’t have the luxury of doing a water change, but luckily you do.

You don’t necessarily have to net your fish and completely drain your pond to change the water. Depending on the size of your pond, you should drain a little and add a certain percentage every week.

  • For large ponds, you should change up to 10 percent of the water weekly.
  • In a smaller pond, you’ll need to refresh at least 15 percent.

Of course, cleaning out your liner and providing a full pond of fresh new water won’t hurt your pond at all, because sometimes pond’s just need to be cleaned.

Best Beneficial Bacteria for Koi Ponds

A product like all MicroLife beneficial bacteria I something I use for my koi pond. It helps to:

  • reduce cloudy water
  • increase water clarity
  • reduce bottom sludge
  • reduce smells when used consistently

Koi ponds, home ponds, small ponds and small lakes is where MicroLife Clear beneficial pond bacteria is used. Larger ponds, lakes, and reservoirs often use the stronger version called, MicroLife Clear Max beneficial bacteria.

How Often to Add Beneficial Bacteria to Pond

For the majority of the year, I advise applying this type of soluble bacteria to your pond:

  • once a week to maintain ideal water quality
  • an additional dose the day after a rainstorm
  • once a week from April to November
  • twice a week when it’s hot

Even when your pond is at its finest, add this helpful bacteria on a weekly basis, but some may argue once a month suits their needs. I beg to differ.

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Hello, I'm Jason. I'm the guy behind I volunteer at my local fish shop and I created this site to offer tips and advice on the fish I care for.