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How to Create a Self-Sustaining Aquarium

While some aquarists find aquarium cleaning to be meditative, most of us would prefer to skip this unpleasant and time-consuming chore. In nature, lakes and rivers are self-cleaning—so is there a way to create a self-sufficient aquarium?  

While you’ll never be able to build an entirely self-sustaining aquarium, you can come close by creating an aquatic ecosystem that mostly supports and filters itself. Do you want to learn how to create a self-sustaining fish tank ecosystem? Here’s what you need to know.  

Table of Contents

How does a self-sustaining aquarium work? 

In a nutshell, a self-sufficient aquarium is intentionally designed so the plants and other aquatic life in the habitat take care of each other and maintain a healthy environment for all.  

In a normal aquarium, uneaten food, waste and decomposing plants release dangerous ammonia into the water. Beneficial bacteria in the water oxidize ammonia into nitrites and then—eventually—into nitrates. Though nitrates are less poisonous than ammonia and nitrites, they can still be harmful and even deadly to your aquatic life in high concentrations. 

This is why it’s so important to regularly perform partial water changes. The beauty of a self-sustaining habitat is that the live plants in the aquatic ecosystem can absorb  ammonia and nitrates, thereby naturally removing them from the water. The plants can also provide a food source for the aquatic life as well as hiding places to help them rest and relax. In turn, aquatic life provides ammonia, which will eventually turn into the nitrates that nourish the plants.  

What are the benefits and drawbacks of a plant and fish ecosystem? 

Creating a self-sustaining mini ecosystem takes work and planning and requires you to carefully choose the plants and aquatic life you add to the aquarium. However, when up and operating, this system can offer lots of benefits. 

The number one benefit of this type of bioactive aquarium is that it can save you the time and effort of continually cleaning your habitat and changing your water. With a normal aquarium, you may need to partially change the water every 2–4 weeks to keep it clean and healthy.  

With the right aquatic ecosystem, you can easily go on vacation or work trips without having to worry too much about your habitat. The right natural aquarium will give you some extra freedom. 

Of course, there are a few challenges to creating a self-sustaining aquarium that you should consider before beginning this endeavor. First, a self-sustaining ecosystem with aquatic life requires a lot of upfront work, planning and effort. Additionally, self-sufficient aquariums are typically more expensive than a basic aquarium setup—so if you are on a budget, this option might not be right for you at this time. Finally, putting together a self-sustaining aquarium doesn’t completely eliminate the need for routine monitoring and maintenance. 

However, many aquarists find that the extra effort and cost of creating a natural aquarium setup are well worth the time saved and extra freedom allowed by a well-functioning habitat. If you want to give a self-sufficient aquarium a try, here are the supplies you need. 

What you need for setting up a self-sustaining aquarium  

An aquarium:

When it comes to creating a natural planted tank, the bigger the better. You’ll need plenty of space for all the plants that will be required to clean the water. At a minimum, your aquarium should be at least 30 gallons and can go up all the way to 200 gallons. Take a look at our aquarium kits for possible options.   

Substrate:

The substrate you add to the bottom of your aquarium plays an important role in developing an ecosystem. The substrate cultivates beneficial bacteria and provides a rooting medium for your plants, helping to stabilize and nourish them. You can purchase a premade substrate mixture formulated for a planted  ecosystem or combine mineral-rich substrate on your own. Put the substrate with the smallest particles on the bottom of the aquarium first—so it should go soil, sand and then gravel.  Using a cupful of substrate from an existing established tank can help to speed up the cycling process as well.

Water:

Both aquatic life and plants can be sensitive to water temperature, pH, chemicals and specific gravity. Make sure to treat your water and invest in a good water testing kit to ensure your water is healthy. Your local Petco also offers free water testing. If possible, use some of the water from a healthy aquarium, which has already been cycled and includes nutrients. 

Lighting:

Plants need the right amount of light to thrive. When preparing your self-cleaning aquarium with plants, don’t forget to look into lighting and hoods. You’ll want to add  lights to the aquarium and keep them on for 8–10 hours a day. Be sure to purchase lights that match the needs of the plants you intend to put in the aquarium or lights that can be dimmed or brightened. Too intense or too little light can damage your plants and invite  algae to flourish. 

Plants:

The number one ingredient to a successful self-sustaining ecosystem is live plants. These natural filters are necessary to absorb harmful ammonia and nitrates in your aquarium’s water. The more plants you have in the ecosystem, the more natural water cleaning power you get. 

When choosing the right plants for your natural aquarium setup, consider the size and growth speed of potential plants, along with their nutritional, lighting and temperature needs. You’ll want to choose plants that will live well together and  have similar needs.  

You can choose from many kinds of plants—including rooted plants, free-floating plants and even plants that grow out of the aquarium—if you want to also experiment with aquaponics.  

Some of the more popular plants for a self-sustaining mini ecosystem are: 

Aquatic life:

The final puzzle piece to complete your self-sufficient aquarium is your aquatic life. Think carefully about what kinds of aquatic life you want. You’ll need to make sure they can live together in harmony and keep the ecosystem balanced. If you add too much aquatic life, they could create more nitrates than the plants can absorb. Larger fish also create more waste, so aquatic ecosystems typically include smaller species. 

Some of the most common fish added to a self-sustaining aquarium are: 

It's also a good idea to add some cleanup crews to your habitat. These aquarium residents will help keep the place clean by eating algae and leftover food. Some good  options include: 

How to start a self-sustaining aquarium

You’ve got all the supplies for your self-sufficient aquarium. Now, how do you put all the pieces together to create a planted aquatic ecosystem that will take care of itself? 

Assemble your aquarium:

Rinse your new enclosure thoroughly with warm water, then add your substrate and décor. Fill with water and treat with a water conditioner. Follow all manufacturer’s instructions and make sure your filter, lights and heater are working properly. Test your water after 24-48 hours to make sure it is at the right temperature.

Add your plants:

When your water is ready, it’s time to add your plants. Follow the instructions for setting up each plant. Some plants may need to be buried in the substrate, while others may do best as free floaters. 

Patience:

This is probably the hardest part of the natural freshwater aquarium process. After adding  plants and a few hardy aquatic life species to the aquarium, you’ll need to wait a few weeks for your ecosystem to “establish”—meaning your plants take root in the substrate and beneficial bacteria begin to multiply. The bacteria are essential to transforming ammonia and nitrites into nitrates, and they need time to colonize your aquarium. If you add too many aquatic life species to your habitat too early, they may become stressed or sick if the nitrogen cycle isn’t yet up and running. Adding some water or substrate from another healthy aquarium or the addition of a bacteria supplement can help jump start the process.

During this waiting period, you may notice algae appearing in the aquarium. This is very common, and you haven’t done anything wrong. As your plants and beneficial bacteria become established, the algae growth will start to subside. In the beginning, though, you’ll want to change your water regularly to prevent algae blooms.  

Add a cleanup crew:

After a few weeks, your aquarium should be ready for some aquarium helpers. Begin with a cleanup crew—such as snails—who will immediately get to work consuming algae. These creatures will help strengthen the nitrogen cycle in the habitat, making it a more welcoming environment for additional aquatic life.

Add more aquatic life:

At last, it’s time to add more aquatic life to your ecosystem. As exciting as it is, be sure to take things slowly. Introduce new aquatic life one by one or in small numbers. Give them time to adapt to the environment and for the environment to adapt to them. Be sure to test the ammonia, nitrite and nitrate levels in your aquarium to make sure they are safe before adding more aquatic life.

Carbon dioxide (CO2):

CO2 is an essential component in a planted aquarium. During photosynthesis, aquarium plants use light and CO2 to produce the food required for growth. As plants continue growing or as more are added to the aquarium, they will use up the supply of CO2 within the aquarium. Adding carbon dioxide is essential to prevent a drop in or overly low CO2 levels, as well as preventing plants from taking in too much bicarbonate, causing fluctuations in pH. Without the addition of CO2, plant growth rates may also become stunted. With new liquid CO2 alternatives such as Flourish Excel, a fully automated CO2 system is no longer a necessity for healthy plants.

Supplements:

Supplementing trace elements such as iron and manganese, as well as items like carbon and vitamins, will help provide additional nutrients so your plants can grow and thrive. Items like Leaf Zone, Flourish and Flourish tabs will help fulfill these supplemental needs.

How do I make my aquarium maintenance-free? 

Despite what the term “self-sufficient” implies, no aquarium can truly run on its own. Even the most balanced aquatic ecosystem  will need ongoing monitoring, maintenance and even some cleaning. In a well-balanced planted ecosystem, you may only need to change 10% of the water every 4 weeks, which is far less upkeep than you’d do for a basic aquarium. 

In the end, being an aquarist means keeping your habitat healthy. A self-sufficient aquarium can relieve you of some of the work and offer you a beautiful ecosystem inspired by the balance found in nature.   

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