Aquarium Substrate & Soil

Using a suitable aquarium substrate is one of the most important decisions you’ll make for your tank. Aquarium soil provides many benefits, from improved filtration to enhancing the overall look of your tank.

But with so many options available – ranging from gravel to soil – it’s important to know what type of vivarium substrate is best for your tank, how to install it, and how to maintain it. In this article, we’ll explain everything you need to know about aquarium substrates.

What Is Aquarium Substrate?

Aquarium substrates are materials that are used to cover the bottom of an aquarium. Typically consisting of gravel, sand, or other materials, this layer can be made from a number of elements, it really comes down to your individual tank’s needs. 

Benefits of Using Aquarium Substrate 

Substrates serve several important functions for both freshwater and saltwater aquariums, such as providing a place for beneficial bacteria to grow. They also create a structure and hiding places for fish and invertebrates.

From a filtration standpoint, they can also help to remove pollutants. Aquarium soils improve water quality and support fish health. They can also be used to add visual enhancement to your aquarium while providing a natural habitat for your aquatic animals.

Best Types of Aquarium Substrates 

Aquarium substrates are an important part of the overall look of your freshwater aquarium. Substrates vary in color, texture, and size and provide a base for important biological processes, like filtration and oxygenation.

When you choose a substrate, the size and shape of your aquarium should be considered. There are several types of substrates available for your aquarium, like gravel, sand, shale, and clay. 


Gravel is one of the most popular substrates used in freshwater aquariums due to it being easy to install compared to other substrate types and its ability to provide a natural look. It comes in a variety of sizes and colors and can range from fine to coarse and sandy.

Larger gravel particles are better for larger aquariums and more established fish, as well as for larger fish that create more waste.

Aquarium Gravel: The Most Definitive Guide | Bantam.Earth

Gravel provides unique benefits for the aquarium including better filtration, oxygenation, and structural support. It also provides a home for beneficial bacteria as well as habitats for various organisms like small crustaceans and worms. 

Here’s a complete guide on aquarium gravel if you’d like to know more about it.


Sand is a popular option for an aquarium substrate due to its ease of use and natural look. This element offers several advantages, such as providing a comfortable base for fish to swim on and providing a natural look.

Sand provides excellent oxygenation due to its porosity, which allows water to more readily flow through. Sand is also more difficult to get stuck in the filter intakes compared to other substrates. 

Aquarium Sand: The Most Definitive Guide | Bantam.Earth

When choosing sand for your aquarium, consider the size of the grain and the color. Finer grain sand is important for smaller fish since it allows them to move more effortlessly, while larger grain sand can scratch their delicate scales. Also, make sure to consider the color of the sand and choose one that matches the other decor in your tank. 

Here’s a complete guide on aquarium sand if you’d like to know more about it.


Clay is a popular substrate for aquariums, due to its ability to improve filtration, oxygenation, and structural support. It is a great choice for those looking for a natural habitat for their fish, as clay replicates nature more closely than other options. 

Clay helps to reduce nitrate levels and encourages beneficial bacteria colonies. It also increases the acidity of the water, which replicates water found in nature. It helps keep the substrate clean by trapping particles and debris, as well as providing an environment in that many aquatic plants thrive. 

A Complete Guide To Turface Soil "Calcined Clay" For Terrariums

Clay is slightly more difficult to install than other aquarium substrates. It needs to be washed well with dechlorinated water before installation to avoid clouding the water. It usually needs to be layered in thin layers, so you may need more of the material than other aquarium substrates. The clay should also be cured over time in order to reduce dust and stabilize pH.

I recommend calcined clay when it comes to a choice between the ideal type of clay for aquarium soils.

How to Choose the Right Aquarium Substrate 

Although aesthetics are important when choosing the right substrate for your aquarium, it’s also important to consider natural filtration capabilities, oxygenation, and structural support for your aquarium. Here are some tips for choosing the right aquarium substrate for your tank.

Consider the Size and Shape of Your Aquarium 

When considering the size and shape of your aquarium, it is important to think about the size and shape of the substrate you choose. Substrates come in various forms and sizes, ranging from small sand particles to larger gravel pieces.

Smaller substrates are better suited for smaller tanks or tanks with small fish that like to explore their environment, while larger gravel pieces are better suited for larger fish and bigger tanks. Additionally, you want to make sure there is enough substrate to adequately cover the bottom of the aquarium.

Too little substrate can lead to ammonia or nitrite build-up, while too much substrate can cause oxygen deprivation and increase the risk of fish injury.

Choose a Color That Matches Your Aquarium Decor 

When it comes to selecting the color of your aquarium substrate, can be a great way to add the finishing touches to your aquarium decor. Aquarium soils come in many different colors, from light pinks to dark blues and even more natural colors like black and tan.

When selecting a color for your aquarium substrate, think about the type of fish you have and how the color will affect their natural behavior. For example, if you have brightly colored fish, then a softer color such as light blues or pinks can help your fish stand out and show off their natural hues.

On the other hand, if you have fish that hide a lot, then choosing a darker substrate such as black or navy can provide a natural camouflage for them.

Consider the Type of Fish You Have 

Considering the type of fish you have in your aquarium is an important factor when choosing the right substrate. Depending on the type and size of fish, certain substrate types are more suitable than others.

If you have more delicate fish that like to swim close to the substrate, a smaller-sized substrate like sand will be more suitable for them, as it can be kinder to their delicate fins.

If you have larger fish that need more structural support and more powerful swimmers, larger gravel will better support their weight when they move around the aquarium.

Furthermore, certain fish are sensitive to changes in their environment and need a substrate that has no toxins and can provide natural food sources.

Fish like breeding cichlids or invertebrates can benefit from substrates like clay, shale, or coral sand that don’t contain sharp pieces of rocks or coral and can provide them with natural nutrients.

Doing your research about the type of fish you have is an important step in selecting the right substrate for them.

How to Install Aquarium Substrate 

Installing aquarium substrate is an important part of creating a successful and beautiful aquarium. There are a few key steps involved in the process to ensure a successful substrate installation.

First, you will need to prepare the aquarium. This includes cleaning the tank and then adding water. Next, it is time to lay the substrate. Depending on the type of substrate you chose, you may want to moisten it to create a more even layer.

Then, the substrate can be poured into the aquarium, vacuuming out any excess and smoothing out the top layer. Finally, it is important to cure the substrate. This includes adding bacterial cultures, seeded live rock, or other information to help establish a stable biological balance in the tank.

Once these steps are completed, you can enjoy a successful and thriving aquarium substrate.

How to Clean and Maintain Your Aquarium Substrate 

One of the most important components of any aquarium is the substrate and it is essential to keep it clean and well-maintained in order to ensure a healthy aquatic environment for your fish, plants, and other organisms.

A regular maintenance routine should be followed in order to keep your aquarium substrate in top condition. 

Regular Vacuuming or Stirring 

Regular vacuuming or stirring of the substrate should be done periodically in order to remove any buildup of debris on the substrate surface. This will help to keep the substrate clean and free of any organic material which can become detrimental to the tank’s inhabitants.

Filter Changes 

Filter changes are an essential part of regular aquarium maintenance and should be done periodically in order to remove any trapped debris and particles from the substrate. Usually, the filter changes should be done every 6-8 weeks and a new filter should be replaced if the old filter gets clogged up or begins to wear out.

The filter should also be cleaned periodically in order to maintain its efficiency. When changing the filter, it is important to rinse the filter in aquarium water as any tap water can contain chemicals that can be detrimental to the aquatic inhabitants.

On top of that, it is important to follow the manufacturer’s instructions for changing the filter and ensuring that the correct filter size is used for the aquarium.

Changing the Water 

The amount and frequency of the water change will depend on the size of the aquarium, the type of fish and plants, and their specific needs. Generally, 10-15% of the water in the tank should be changed once a week and a full water change should occur every month or two.

When changing part of the water, a siphon hose should be used to vacuum out the bottom of the tank, also known as the substrate. When changing the full water, it is important to not remove more than 25-50% at one time, as this could harm the inhabitants of the tank due to the drastic change in water parameters.

Bonus: Pro Tip

It is important to remember that the substrate is home to a variety of beneficial bacteria and organisms which are essential for a healthy and balanced aquarium. Therefore, it is important to avoid over-cleaning or disrupting these beneficial bacteria as much as possible.

Careful consideration should always be given when cleaning the aquarium substrate in order to ensure the well-being of your aquarium inhabitants.


Using aquarium substrates is an essential part of keeping a healthy and attractive aquarium. From providing oxygenation and filtration to enhancing the look of your aquarium, the benefits of using substrate are clear.

Not only is substrate helpful for your aquatic life, but it also provides a nutrient source for your plants. With the right substrate, you can create a beautiful and thriving environment for your fish and aquatic plants to reach their highest potential.

The Best Types Of Aquarium Substrate

Frequently Asked Questions

The best substrate for aquariums is gravel, as it provides an optimal environment for beneficial bacteria, helping to cycle and balance the aquarium‘s water. Gravel also comes in a variety of colors, so you can find one to perfectly suit your tank.

Aquarium gravel and substrate are both materials used to create the bottom layer of an aquarium, but they serve slightly different purposes. Gravel is ideal for aquariums with live plants, as it serves as a platform for their roots and allows for easier maintenance.

A substrate is a finer, more absorbent material (usually clay), making it best for aquariums with no living plants as it helps to regulate the aquarium stratum. Both materials come in a wide range of colors and sizes, so you can choose the one that best suits your aquarium‘s requirements.

A substrate in a fish tank is a bedding material that is placed on the bottom of the tank to provide a surface for beneficial bacteria to grow as well as a comfortable environment for fish and other aquatic species to live in.

It can include everything from gravel to sand and other natural materials. Substrates also help create a naturallooking habitat, adding aesthetic appeal to the aquarium.

For the best results when creating a planted aquarium, you should use a substrate that will support the growth of aquatic plants.

This includes a specialized substrate that provides nutrients and allows root growth, such as Aquasoil, as well as standard aquarium gravel. Be sure to choose a substrate that also meets any requirements specific to the type of plants in your aquarium.

Yes, substrate is important in an aquarium and helps with filtration, aesthetic appeal, and providing beneficial minerals that can supplement the fish‘s diet.

Live substrate also supports beneficial bacteria growth and helps to maintain pH levels. Substrate is also essential for providing shelter for aquarium inhabitants and can help to create an environment that is conducive to spawning.

It depends, there are many benefits to a barebottom tank. It can help simplify maintenance, as it is much easier to clean than a fully planted tank. Additionally, it can reduce the growth of unwanted algae and bacteria. Finally, it looks great because of its unique and minimalist design.

It is recommended that aquarium substrate should be changed every 1 to 5 years depending on the type of substrate used.

Certain types of aquarium substrate, such as gravel and crushed coral, require more frequent replacement. Natural aquarium substrates such as sand should be replaced every 3 to 5 years.

A planted tank should have a substrate depth of at least 57 cm to provide enough space for root growth and to allow for proper water and nutrient exchange.

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