Step 7 - Build a Pond Ecosystem

When construction is complete, it’s time to build an ecosystem. A properly functioning ecosystem is vital to a natural pond because it takes care of many maintenance issues by itself. This is important for water clarity and algae bloom prevention while keeping certain pond residents numbers in check.

Okay, you have filled your pond with water. The water is holding well and the overflow is fully functional. You’ve achieved a great accomplishment by making it this far so, congratulations! The hardest labor is now behind you and it’s time to start having some fun. It’s now time to learn how to build a pond ecosystem. The first order of business is to add to a quality beneficial bacteria product to the water. The number of gallons of water determines the dosage amount; follow the directions carefully.

Build a Pond Ecosystem

Water quality matters

If you filled the pond with chlorinated tap water, use a product to neutralize the chlorine and other heavy metals. There are many liquid chlorine removers on the market that are cheap. Simply add the solution to the pond after you filled it up. I prefer using a filter that hooks directly to the water spigot. 

I keep the water pressure on low so it spends more time passing through the filter. Sunlight also causes chlorine to dissipate, but please don’t count on this alone. City water has chemicals that kill bacteria which also kill off the beneficial bacteria in your pond. We certainly don’t want that to happen. If it does, the water clouds up. To build an ecosystem, healthy beneficial bacteria is a must. It’s the primary building block of any pond’s ecosystem.

Using city water for your pond | Natural Pond Lover
An inline water dechlorinator with a filter hooks directly to a water spigot.

See the video here

Adding plants and snails

Next, it’s time to add some plants. Go to town on it, aquatic plants are great for the ecosystem! In fact, plants are another essential element of a natural pond. Be sure to use oxygenating plants such as hornwort and anacharis. Water lilies are great too, however, they need fertilizer to grow. Add those a little later. Let’s first concentrate on our oxygenating plants.

This is a fine time to add snails. Simply throw them in the water and they’ll find their way. Snails are great for cleaning up organic matter and keeping pond water clear. They also feed on any grass, leaves and even pine needles that happen to fall in the pond. Some species of snail are asexual and multiply without a mate. Only add snails to a new pond once. Try to stick with snails which are found naturally in your range. Most likely those are legal. Invasive snails do far more harm than good.

How to Build a Pond Ecosystem | Natural Pond Lover

Add ‘some’ fish

Next, let’s add some simple fish. No big fish yet, just add some mosquito fish. Enough oxygen is available and they’ll feed on any bugs they come across. While they also eat some algae, please don’t count on mosquito fish for algae control. Mosquito fish are livebearers and quickly multiply on their own. Like snails, add mosquito fish only once. Wait until after the bacteria bloom has concluded to add larger fish.

Wait, what’s a bacteria bloom? I was just getting around to that.

Sand as a pond medium

Bacteria Bloom

A bacteria bloom is unavoidable when starting a new fish tank. The same goes for a new pond. Whether you use sand, soil, or river pebbles, a bacteria bloom is bound to occur. This usually happens right away and lasts anywhere between four to six weeks (four being the average). It also depends on the season and outside temperature. Cooler temperatures stall the progress of a bacteria bloom.

Don’t worry about the cloudy water at this point and don’t spend money on a product that settles water particles. Such a product is unnecessary and useless during this time.

Bacteria blooms are normal and essential for the ecosystem of a pond. Eventually, you’ll start to see through the water, eventually down to the bottom. That’s when business starts to pick up assuming the pond isn’t overstocked with inappropriately sized fish. Excess ammonia from fish urine stalls the progress, if not halt it altogether.

The frequency of bacteria blooms

Bacteria blooms are not limited to when a new pond is first becoming acclimated. They occur at any time of the year for different reasons. Many times it’s attributed to the change of seasons, especially when winter turns to spring. This is when you need to add a beneficial bacteria product.

Beneficial bacteria turns dormant during the winter. Bacteria begin to multiply again with the warmer weather of spring. While the water might become cloudy during this time, spring induced bacteria blooms shouldn’t last as long as one from a new pond.

Lesser predators

The basic foundation on how to build a pond ecosystem thus far,

  • dechlorinated water
  • beneficial bacteria
  • plants
  • snails
  • mosquito fish.

After your bacteria bloom is complete, you’ve reached a new level of achievement. Congratulations, once again!

Bullfrog and Common pond frogs | Natural Pond Lover

From this point, you can add some frogs and/or tadpoles. While we’re crossing into predator territory, frogs won’t hurt the foundation you’ve worked so hard to create. On the other hand, don’t overdo it, especially when adding bullfrog tadpoles. If it’s springtime, you may notice that hundreds of small, black tadpoles found their way into the pond by themselves. These are toad tadpoles. They won’t harm anything. In fact, they’re good because they feed on algae and mosquito larvae.

Once the water has cleared and the plants have taken, you can start adding some bigger fish. Don’t overstock! You can always add more fish later. Actually, there’s never a good time to overstock a pond, but I think you know what I mean. Add the proper amount of larger fish after the first batch has acclimated (and that space comfortably provides).

Hawk | Natural Pond Lover
A hawk visits my pond off the patio just before nightfall. This is a predator at the top of the food chain.
Water snake | Natural Pond Lover
Water snakes are on the top of the food chain in a natural pond ecosystem.

Top predators

We have had fun learning how to build a pond ecosystem. Now we’re working our way to the top of the food chain. Game fish, turtles, raccoons, bobcat, snakes, hawks and alligators are all examples of top predators. Some find their way to your pond on their own.

I imagine the only ones from the list that you may want in your pond are turtles and/or, game-fish. Wait until the second season to add largemouth bass, not the first. Remember, adding bass also add limitations to what can exist in the pond. Bluegill can be added the first season if they’re yearlings. Koi and small goldfish can be added the first season if you prefer to go that route. Again, don’t overstock! Be careful with any fish in the carp family, they’re dirty fish.

Have water lilies or some type of cover for your pond fish to hide under. Hawks are a pain in the neck for pond owners.


While I’m more of a reptile and amphibian person, other people love the different kinds of birds a pond attracts. Some birds only take a quick drink or bath. Other birds are predators that try to snatch up your fish. Koi have bright coloring and stick out like a sore thumb. Game-fish and mosquito fish are colored to blend in with their environment. This camouflage keeps them at less risk to predatory birds. While water lilies help in hiding brightly colored fish, it’s not a guarantee. Are there any guarantees with nature?

I hope this article was helpful in teaching you how to build a pond ecosystem. You’ve come a long way on this journey, be proud of your accomplishments thus far.

How to build a pond ecosystem