how to build self sustaining aquarium

How To Build Self Sustaining Aquarium in 4 Steps

Maintenance is the number one complaint from people who own aquariums. It takes time and is required to keep a healthy aquarium. There is a way to minimize the amount of maintenance needed for your fish tank.

A self-sustaining aquarium works without much supervision or interference from humans. Like on our planet, thousands of species coexist in harmony; you can attempt to recreate such a scenario under controlled parameters. 

This guide will teach you everything you need to know to properly create a self-sustaining aquarium. We’ve included a step-by-step manual so you can nail it on your first attempt. You’ll be having effortless fun with your own self-sustaining aquarium in no time.

how to build self sustaining aquarium

What is a Self Sustaining Aquarium?

A self-sustaining aquarium is a miniature underwater ecosystem that needs no human interference (or minimal). The key concept to understand is the food chainThe food chain is the network of links that starts with food-producing organisms and ends with predators.

This concept is the basis of a self-sustaining aquarium. You need to create a food chain that works flawlessly, so the life cycle becomes circular. This is to say that you have food creators, predators, and bacteria coexisting in harmony. 

Why You May Want a Self Cleaning Aquarium

Now that we have been through what self-cleaning aquariums are let’s take a look at the benefits of having one. We’ll divide the benefits into two: for you, the owner, and them, the life inside.

Benefits for You

Less Maintenance Effort 

If properly designed with the right critters, you can forget about most maintenance work. Having critters that feed on algae helps to keep your tank clean. A self-sustaining aquarium also drastically reduces the need for scheduled water changes.  

Go on Vacations Without Worries

With a self-sustaining aquarium, gone will be the days in which you had to get someone to take care of your fish while you were away. Since the food chain will be working as a cycle, you don’t need to bring any external food to the ecosystem.

Cheaper in the Long Run

Although you might have to make a bigger investment upfront, a self-sustaining aquarium’s maintenance costs are close to none. Furthermore, you can even expand at no cost taking material from your ecosystem to build the next.

Watch Life at its Purest Form

The biggest difference between a traditional fish tank and a self-sustaining, self-cleaning aquarium is that you can imitate the real world. Indeed, you don’t need to feed the fish or remove anything from the water artificially. Having a small underwater ecosystem is like putting a window at the bottom of a pond, and watching nature work its magic.

Benefits for Them

Less Stress

If you’ve ever owned a regular aquarium, you know that you have to change large quantities of water. Mostly during times that involve moving fish to another tank. This is an annoying process for humans and a very stressful moment for the fish. You can solve both problems at once with a self-sustaining aquarium.

A Home Away from Home

By creating the ecosystem needed for a self-sustaining aquarium, you’ll be providing conditions for your fish that are as close to their natural habitat as it gets. Moreover, you need to achieve such a status for the ecosystem to work.

Give Them a Better Life

There are no synthetic products that can recreate what happens in your fish’s natural habitat. Thus, the food will be better, the environment will be better, and their life quality will be better. 

Step-By-Step Guide for How to Build Self Sustaining Aquarium

We’ve gone through what a self-sustaining aquarium is and why you should have one; now it is time to tackle the subject straight on. Here is a detailed guide about creating your personal aquatic ecosystem.

Step 1 – Get the Materials

You can purchase a self-sustaining aquarium kit that will include all the elements you need. If you prefer to choose each item, below is the list of materials you will need to get started with this project. 

The Aquarium

First, you will need to decide on what fish tank you want. We recommend something larger that is easier to work with. A tank between 30 and 200 gallons of water is ideal. 

Keep in mind you will want all the walls to be transparent. It will need exposure to the sun and as much natural light as possible for a self-sustaining aquarium to work properly. 

The Substrate

The substrate that you choose will be paramount for your aquarium’s life quality. Some people underestimate the role that bacteria occupy in the welfare of ecosystems. A good self-sustaining aquarium is built from the ground up.

The substrate accomplishes three essential tasks:

  • The right quantity and material in the substrate at the bottom of the tank will help you cultivate the needed amount of bacteria for your ecosystem.
  • If the bottom is rich and appealing for the bacteria, it will remain at the bottom, staying away from the ventilation system and the plants.
  • Plants count on the rich substrate to nourish and grow. Plus, that is where their roots will go; hence the better the substrate, the healthier they will be.


You need to measure so many things in the water to make sure that your fish will live happily in it that you can’t just put some tap water in and think you`re good. Things like pH, temperature, salinity, and such are paramount for fish welfare and sometimes survival. Don’t overlook this item; get a good water-testing kit and the right type of water your fish need. 


Filters could take an entire post of their own. One group of people think they are paramount for keeping the water clean and helping your fish get the right amount of oxygen. On the other hand, many people think that a self-sustaining aquarium shouldn’t have an air filter.

The idea is to emulate nature as closely as possible, avoiding using human-made technology to keep life in the aquarium in perfect harmony. If you search on YouTube, you’ll find dozens of videos showing examples of no-filter, self-sustaining aquariums.

That being said, you can always get the kind of filter you want for your fish tank. 

Light Source

The best light you can give to your self-sustaining aquarium is natural sunlight. Fish are mostly like humans in terms of their sleeping cycle, so as long as you can keep them illuminated for several hours a day, they’ll be fine.

On the other hand, if you happen not to have any natural sunlight in the spot your aquarium will be, you will have to help your fish with some additional artificial lighting. We recommend LED lights and a timer so you won’t ever forget to let the sunrise in your ecosystem.


The decoration is completely optional. You can choose to add some pieces to make it more interesting, but it is not a must. Moreover, with the number of plants and life you’ll have in the landscape, they will not be the outstanding piece they could be in a different kind of aquarium.

If you decide to go for some decoration, make sure that it will not change the water composition. A good way to check on this is to fill a bucket with water and take all measurements. Then, sink the piece(s) for a week and measure again. If values don’t change drastically, you’re good to go. Otherwise, you might consider avoiding those ornaments.

Finally, choose an ornament that will not have too much paint chipping off from the exterior. That debris could prove to be deadly for your perfectly-crafted food chain.

Step 2 – Put it All Together

Before you put any living inhabitants in the water, you need to make sure everything is set correctly. A word of warning is that you set the tank up on the spot where you plan to leave it (you won’t be able to move a full tank afterward). 

Let’s break it down into sub-steps:

1. Clean the tank thoroughly to avoid any unwanted contaminants

2. Add the substrate. If you bought a kit, follow the instructions; otherwise, add it from smaller textures to bigger textures.

3. If any of your plants will be rooted in the substrate, now it’s time to do the underwater gardening operation.

4. Filtering, pumps and artificial aids should be set at this moment.

5. Now it’s the time for the decorations if you plan to include any in your fish tank. 

Step 3 – Add the Water and Test it

In this third step, you should slowly add the water to test that everything works properly. This is also the time to take all the measurements and ensure that the habitat is good for your fish. Finally, it is time to add the bacteria and microorganisms such as snails and other micro-critters.

Step 4 – Let the Fish in

After testing that everything works great and taking the proper measurements, it’s time to let the fish inside. Make sure you also pour the water they came in so you can add any bacteria and microorganisms from it.

One thing you should do is to continue feeding your fish until you make sure that the food chain is working properly. Also, because you want to let the algae and plants reach maturity and the microorganisms to multiply. 

Best Fish for a Self Sustaining Aquarium

We’ve just been through the non-living part of your aquarium. Now it’s time to take care of your guests. These are our suggestions.


Adding to the fact that they do not have a strict dietary requirement, they are rather passive by nature. Although they are probably not the best cleaners, they are colorful and have a very long lifespan. 


These algae-loving fish are great companions for the swordtail and share the same lack of aggressive behavior. They are not the most visually appealing fish globally, but they surely help cleaning around and adapt very easily to any situation.

Bristlenose Plecos

These funny-looking fellows need two things for happiness: room to swim and algae to feed on. They move around pretty fast and usually grow to be 15cm long. They will surely add some fun to your self-sustaining aquarium; make sure you have enough algae to keep them well-fed and happy.

Hoplo Catfish

If you ask me what fish is ideal for your self-cleaning aquarium, it is the Hoplo Catfish without any shadow of a doubt. They aren’t good looking fish, but they are hard-working cleaners taking care of some algae.

Bloodfin Tetra

Bloodfin Tetras measure two inches and live up to five years. These small and beautiful fish won’t eat your plants and will give your tank a silver lining of beauty as long as they have enough room. The best of it all? They don’t cause any trouble and require almost no care. 


Colorful, peaceful, and omnivorous, platies can bring many things to your aquarium, including bright colors. They don’t eat other fish but eat mostly anything else, like algae, so it will help keep things tidy and beautiful. They are born in a wide diversity of colors for you to choose from.

Neon Tetra

Also, these are the most colorful siblings of the lineage from the Tetra family. You can add some 3D texture to your tank without much effort since they require close to no care and love to swim around a lot. They move in groups of six and have a similar lifespan to the Bloodfin. 

Best Plants for a Self Sustaining Aquarium

Now that you know who your guests shall be, let’s talk about the food chain’s basis, the plants in your self-sustaining aquarium.

Moss Balls

Moss balls have two main characteristics that make them great besides the looks: they absorb nitrate and produce oxygen and are very easy to maintain. Just drop some of them at the bottom of the aquarium or get creative and make a beautiful shape, and they will do the rest.

Water Lettuce

This floating plant’s long square leaves look great on any self-sustaining aquarium. Although that alone could be a great reason to choose them, they will help you reduce the nitrate levels. 


This variety of floating aquatic plants offers lily-shaped leaves and also helps with the reduction of the nitrate levels in the water. The only thing you have to bear in mind is that it is a fast-growing kind, and you will need to trim it often.

Water Sprite

If you don’t want a nitrate absorbing jungle, you’ll have to do some trimming now and then because water sprites grow really fast. That being said, this type of fern looks great at the aquarium’s bottom.

How to Maintain a Self Sustaining Aquarium

The whole idea behind a self-sustaining aquarium is that it should require minimal to no human intervention. All tanks will require maintenance on some level. Here are a few easy steps you will want to keep in mind. 

Water Changes  

Although not everybody recommends you perform water changes on your self-sustaining aquarium, you can change 10-20% of the water once a week. Make sure you do not cause drastic changes in temperature or take away too much bacteria.

Remove Algae from the Walls

You shouldn’t have this problem with the right fish selection. If you happen to have too many algae blocking sunlight, you will need to remove it. Use a non-intrusive element like a magnetic algae scraper.

Do Some Trimming 

Some of the plants in your aquarium will require some trimming now and then. Trim them gently and often so you can avoid an underwater jungle. Bear in mind most fish love to have room to swim. 

Final Thoughts on How to Build Self Sustaining Aquarium

Hopefully, by now, you know everything you need to know to create this underwater universe in your home. All you need to do is pick wisely from the categories above and apply our advice to start this beautiful journey into self-sustaining underwater life creation.

Creating your own ecosystem requires a bit of effort upfront, but it will demand very little attention in the long run. You will very likely marvel at how underwater life grows and lives on its own with absolutely no human interference. Furthermore, you’ll experience a small world growing in your living room.

Looking for tips about aquarium maintenance? Head over to our Aquarium Maintenance & Repair section to see more.

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