Is Sand or Gravel Best for Your Fish Tank?

Image of a yellow fish inside an aquarium

Designing an aquarium is an enjoyable and rewarding experience, as it allows you to create the perfect habitat for your fish and marine life. One of the first and most important decisions you’ll make is the type of substrate to use at the bottom of your tank. While many believe that any type can be used in a tank regardless of its inhabitants, it greatly influences their quality of life, so you’ll need to choose correctly. 

Many substrate types are available on the market, and each one determines the setup of your aquarium and whether or not your fish, invertebrates and plants can flourish. Sand and gravel are the main types of substrate used in fish tanks. Although gravel tends to be the best option for most wildlife and plant life, there are some scenarios where sand is more suitable. If you’re curious about what aquarium substrate is best for your fish tank, you can find everything you need in our complete guide. 

Read on to learn more about aquarium substrates, including the different types of sand and gravel and their benefits and drawbacks.


  1. What is aquarium sand?

1.1. Types of sand

1.2. Advantages of fish tank sand

1.3. Disadvantages of fish tank sand

  1. What is fish gravel?

1.1. Types of fish gravel

1.2. Advantages of fish gravel

1.3. Disadvantages of fish gravel

What is aquarium sand?

Aquarium sand is a reliable, cost-effective substrate commonly used for the bottom of freshwater aquariums. It creates a simple, tranquil appearance similar to a sea bed and comes in various colours and textures. 

While natural sand comprises tiny pieces of shells, rocks and other raw materials, aquarium sand is usually made of quartz, coral, and minerals or manufactured using a silica base. All types of sand are uniform in shape and size and typically measure from 1/16 to 2mm. As sand particles have smooth edges, they cannot injure aquatic animals and organisms.

Types of sand

Natural and artificial sand is used in many industries, from construction to manufacturing, with artificial varieties composed of all types of materials to suit their purpose. This can cause confusion if you’re looking for a suitable aquarium substrate, as many sand products are unsafe for aquariums and freshwater tanks. To help you to choose a safe option, we have listed some of the most common types of aquarium sand below:

Live sand 

Live sand is the most natural type you can have in your aquarium, as it contains natural aquatic bacteria and other microorganisms that can benefit your tank’s ecosystem. Bags of live sand usually contain fresh or saltwater and the substrate, so you don’t need to rinse it before adding it to your tank. The bacteria in live sand help to break down waste products and effectively maintain water chemistry. 

This type of sand is suitable for many aquatic species that prefer a high water pH. Just be sure to research whether live sand is suitable for your aquarium, as it is unsuitable for some freshwater species. As live sand isn’t specifically designed for fish tanks, it may cloud the water or clog the filter until it has settled.

Plant sand

Plant sand is manufactured from iron-containing clay ground into sand particles and is available in limited colours. Its porous structure allows water to flow through it. This helps healthy bacteria multiply, providing plants and other organisms with the nutrients they need without altering water chemistry.

Pool sand

Pool sand is a natural product that is usually pale in colour. It is cleaned and broken down into uniform-sized sand particles that can be used in aquariums. While it is slightly heavier than artificial sand, it’s less likely to cloud the water and clog your filter, making it more economical. Pool sand also doesn’t alter water chemistry. However, it is unsuitable for most planted tanks, so it should mainly be used in fish tanks without plant life. 

Artificial sand 

Also known as play sand, artificial sand is usually manufactured from silica and comes in various bright and natural colours. It is usually coated to prevent the colour from coming off, so it is unsuitable for planted tanks. As it is chemically inert, it doesn’t alter the chemistry of your water. Although lighter than pool sand, it is more likely to clog filtration systems; however, it is more economical than other sand types. 

Advantages of fish tank sand

  • Creates a smooth, attractive appearance that recreates the aesthetic of your aquatic life’s natural habitat.
  • Suitable for tanks containing freshwater invertebrates, cichlids or burrowing fish.
  • As waste and debris remain on the top layer of sand, they are easily removed by your filter or a hose. 

Disadvantages of fish tank sand 

  • Sand isn’t suitable for every tank and can have various limitations when used in freshwater aquariums.
  • If the type of sand you’re using isn’t porous, water can’t flow through it. This can result in multiple dead zones within your tank where oxygen is depleted. To prevent this, you’ll need a good filtration system and wide water circulation to treat all water. 
  • As sand that isn’t porous can prevent nutrients from being absorbed by your plants’ roots, you should avoid using these types in planted tanks. 
  • Tanks with sand substrates can only use certain types of filters that are unlikely to come close to it. Its small, lightweight particles can easily clog filtration systems and hoses. 
Image of a group of fish inside a gravel filled fish tank

What is fish gravel?

Fish gravel is the most common type of substrate as it is suitable for most aquarium types. There are many different options, as it can be manufactured to vary in size, colour, shape and composition. It is usually made from refined materials such as quartz or sandstone to create a specific shape and size. 

Whether you’re looking for fine grains or large pebbles to sit at the bottom of your fish tank, there’s an option to suit all types of fish and plants so you can create the perfect environment for them to grow in. Manufactured gravel can be found in dyed or painted varieties, which are sealed to maintain the colour. Natural types of gravel are porous and allow bacteria and microorganisms to grow throughout the substrate, helping to convert toxic waste into a safer material.

Types of fish gravel

There isn’t a specific definition for aquarium gravel. However, its diameter ranges from 2mm to ¼ inch. Like sand, gravel is also used in various industries such as construction, many of which aren’t safe to use in aquariums as they contain heavy metals and other toxic chemicals that have the potential to poison the water. You should only use products made for aquariums to ensure the best results. We have listed some of the most common types of fish gravel below:

Live gravel

Like live sand, bags of live gravel contain fresh or saltwater with bacteria and microorganisms, so there’s no need to rinse it before adding it to your tank. The nutrients in this type of gravel can help your plant life to thrive, creating a balanced ecosystem for your fish and invertebrates. You can find a range of sizes and colours to suit your tank, each suitable for most freshwater species.

Natural/river gravel 

Natural gravel is an excellent choice if you wish to make your aquarium as authentic as possible. This type of gravel is usually collected from riversides and gravel pits and cleaned and refined to display a similar size and shape. It is porous, promotes healthy bacteria to grow throughout your substrate, and prevents dead zones, as it isn’t coated with a sealant. 

Natural gravel can be found in various natural colours and textures. It is suitable for most freshwater species and does not alter your water chemistry, making it an excellent choice for a vibrant aquarium.

Clay gravel

Clay gravel is another excellent option for freshwater species, providing many benefits. Made from iron and mineral-rich clay, they allow water to flow throughout your substrate and allow healthy bacteria to flourish. This can help prevent dead zones in your tank and give plants the nutrients they need to grow. 

While it is usually more expensive than other types of gravel, they are suitable for most freshwater organisms and don’t alter water chemistry. One of the only drawbacks of this gravel type is that it is often very dusty, so it needs to be rinsed thoroughly before adding it to your tank. 

Artificial gravel

Artificial gravel is usually manufactured from silica, industrial resin or natural gravel covered with an acrylic coating. It requires little rinsing before adding to your tank, is suitable for various freshwater animals and doesn’t alter your water chemistry. 

One of the benefits of using acrylic gravel is that it is available in various colours, shapes and sizes. However, colours may fade or chip over time. It’s important to note that the smoother surface of acrylic gravel isn’t the best environment for healthy bacteria to accumulate, although it is still possible.

Advantages of fish gravel 

  • Fish gravel is easier to maintain than sand, as it encourages healthy bacteria and other ammonia-reducing microorganisms to thrive. This promotes the breakdown of waste products and helps to maintain a healthy ecosystem in your tank.
  • Gravel is suitable for nearly all freshwater fish and invertebrates. It also aids the growth of aquatic plants, allowing their roots to take in nutrients from the water that flows through the substrate.
  • Choosing a gravel substrate allows you to choose from a wider variety of filtering options, including under gravel and hanging filters.
  • Gravel hides debris more effectively than sand, as it can fall into the gaps and sink down into the substrate.

Disadvantages of fish gravel

  • Having a gravel substrate can make it more difficult to eliminate blue-green algae if you have an outbreak due to the water flowing through it. A sand substrate will limit this to the surface layer as it comprises smaller particles.

Now that you know about the different types of sand and gravel, along with the pros and cons of using each substrate type, you’ll likely better understand which option will work best for your aquarium. Whether you choose sand or gravel, each substrate type offers different benefits, so learning more about the plants and animals you plan to have will help you to decide which type is the most suitable.

Changing the substrate in your fish tank once you have begun to create an aquatic community is difficult. To avoid these difficulties, choose the substrate best suited to the fish, invertebrates and plants you plan to keep long-term. 

At Discount Leisure Products, we offer an extensive range of high-quality aquarium sand and gravel in various colours, sizes and shapes, so you can find an ideal option to add to your aquarium. Explore our collection and start building your aquatic community today. 


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