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Best Fish Tank Substrates for 2022

With very few exceptions, all fish tanks need some sort of material (aquarium substrate) on the bottom.

It gives fish somewhere to hide, which is perfect especially for those breeds who like to burrow. Stray bits of uneaten food can land on the substrate too, making it a) easier to clean for you and b) the perfect surface for bottom-dweller feeders. The substrate also reduces reflections in the tank, so can reduce stress.

There are loads of more scientific benefits too. Some substrates can help change the chemistry of the water, too, increasing pH levels and hardening water for specific rarer fish.

Aquarium substrate can generally be either gravel or sand, but other materials are also available depending on the conditions your fish need to live in and whether you have a planted tank. You can keep a bare-bottom tank for messy fish like goldfish, but they can be harder to care for.

Because it shouldn’t be changed or altered when your fish are in their tank, it is vital to get it just right when initially setting up your aquarium. When looking for an aquarium substrate, you want something specifically catered to fish. Minimal dust and something small enough to bury in is ideal. If you have plants, you also will want substrate which complements them.

We have included the best pick for all types of fish tank substrate below, ensuring they are safe for your fish, popular with owners and great value.

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    Our Top Picks

    Image Product Details
    Pets At Home Natural Mix Aquarium Gravel
    • Made from silicate aggregates
    • Can be used in any water
    Check Price
    Tetra Complete Substrate
    • Gritty texture to lower chance of it moving
    • Easy to place
    Check Price
    Roman Gravel Sand
    • Choice of colours
    • Good for planting
    Check Price

    The Top Fish Substrate Reviewed

    Pets At Home Natural Mix Aquarium Gravel

    A great mix of different colours, gravel sizes and silicate types for your tank to really have that natural sea feel and keep all of your fish happy.

    It looks decorative but also gives your fish somewhere perfect to explore and play in. the stones will need rinsing thoroughly before they are placed in your tank, but the colourfast resin coating will ensure that the colour doesn’t start leaking into your water over time. This also means it won’t affect the pH levels or cloudiness.

    If you have plants, it makes a perfect medium due to the smaller size, allowing good bacteria to grow and the plant to remain in place. You can purchase it in a 2kg or 8kg bag, so you get the perfect amount for your tank size.


    • Made from silicate aggregates
    • Can be used in any water


    • Colours: Natural Mix
    • Bag Size: 2kg/8kg
    • Tank Type: Any

    Tetra Complete Substrate

    When your fish need plants to thrive, you don’t only need to give your pets something for the bottom of the tank but your plants, too.

    This is a substrate for new tanks, which is able to activate strong plant growth. It is ready to use and promotes fast, secure adhesion and resistant roots for long-term installations. It is a soil mixed with gravel, so the tank will need to be emptied before using.

    You can still place a level of sand or gravel over the top, which is perfect for holding it down or looking a bit more decorative. The texture is quite gritty however, so less likely to float around in time.

    Around 2cm of this substrate is needed, so calculate well before buying.


    • Gritty texture to lower chance of it moving
    • Easy to place


    • Colours: Brown
    • Bag Size: 5kg
    • Tank Type: Any

    Marina Decorative Aquarium Rainbow Gravel

    Hugely colourful gravel can really help when your fish are also hugely colourful, such as a school of Tetras.

    With the contrast of the green plants and decorations, it will make a striking display. This Marina collection is dust-free, non-toxic and epoxy-coated, making it perfect for use in an aquarium. It is the ideal size to provide a perfect breeding ground for bacteria colonisation, to maintain clear water.

    As with all gravel, wash before you use to remove any dust. Users have said that the colour still remains as vivid one or two years on, which is great news for longevity.


    • Good medium size
    • Epoxy-coated to encourage good bacteria


    • Colours: Rainbow
    • Bag Size: 450g, 2kg
    • Tank Type: Any

    Roman Gravel Sand

    Sand is great for burrowing fish or those bottom-feeders, or indeed as a base under your gravel to keep plants and other decorations secure.

    Available in four colour varieties, you can pick the one which will make your tank look just the part. It is great to use as a plater medium due to the fine size, and it all looks really dazzling under lighting.

    Sand needs turning to aerate it every so often, but this one is easy to clean with a vacuum held far enough away as any dirt just sits on the top layer. It is great for axolotls or bottom-dwelling fish as it is soft and easy to walk on or burrow into.


    • Choice of colours
    • Good for planting


    • Colours: Black, Pewter, Quartz, Speckled
    • Bag Size: 8kg
    • Tank Type: Any

    BiOrb White Feng Shui Marble Aquarium Pebbles

    Pebbles are best used as decorative elements or to secure your ornaments and plants if you have fish who like to pull and play with them, moving or bringing them out.

    They are all large stones, so won’t easily be disturbed by small fish. They’re ordinary smooth stones, so will need taking out and cleaning occasionally, but once they have been washed they are safe for use in your tank.

    How many you get in a bag differs, unfortunately, but in general, it seems to be between 8 and 12 large stones to make up the overall weight which should be enough for decorative issues. If you’re thinking that they’re expensive so you should nip to the beach and pick some up instead, think again – these ones are the safest and least toxic for your tank water.

    These are also ideal for using in a dedicated small BiOrb with just one or two fish in.


    • Large
    • Great as decoration or security


    • Colours: White, Black, Green, Red
    • Bag Size: 912g
    • Tank Type: Any

    Fluval Stratum Volcanic Soil

    If you have a planted tank and living plants which require just as much care and attention as the actual fish, getting the best layer of any substrate to help them stay alive is vital.

    This volcanic soil, which looks like little balls, stimulates strong plant growth, making it better than using sand or stone. It helps keep the tank at a neutral to slightly acidic pH level, so is best for tanks where the fish require this level.

    The plant roots easily branch into the substrate, spreading as they grow and becoming more secure for any fish who are a bit mischievous and like to pull at them. If you have shrimp it can also be great, as they can hide in the substrate until they are old enough to come out and not be bullied or threatened.

    It’s not good for any fish who like to move the tank bedding around, nor African and Central American cichlid species, goldfish or koi. It also can’t be used in saltwater, and shouldn’t really be used with other gravel mixes.


    • Lightweight and porous


    • Colours: Black
    • Bag Size: 2kg, 4kg, 8kg
    • Tank Type: Plant, Shrimp, Tropical

    GardenersDream Coloured Aquatic Gravel

    One of the best for overall choice, in terms of both colour and bag sizes, so you can find the perfect match for your tank.

    It is not toxic and remains dust-free once initially rinsed. Each piece is between 3mm – 8mm, so it is good for little fish who like to burrow and hide as well as larger ones who may want to move things around.

    Great quality, don’t be put off by the fact it can also be used as a plant pot topper. If you have some leftover, at least this means it will still come in use!


    • Colour choice
    • Good quality and low dust


    • Colours: Black, White, Green, Orange, Yellow, Blue, Purple, Red, Rainbow
    • Bag Size: 1kg, 2.5kg, 5kg, 10kg, 20kg
    • Tank Type: Any

    Aquatic Roman Gravel Natural Cream

    A choice of ten neutral finishes and colours means you can pick the exact look you’re after for your fish tank.

    It is suitable for cold water, tropical and saltwater tanks, and the small size means there is a higher surface area which makes it ideal for anaerobic activity and good bacteria production. It also makes for the perfect planting medium.

    Suitable for bottom feeders and barbed fish as the edges aren’t too harsh and sharp. As they’re made from silica aggregates, they’re pretty inert and they’re covered in colourfast resin to ensure there is no pollution in the tank.


    • Colour choice
    • Good for all tanks and fish


    • Colours: Choice of 10
    • Bag Size: 8kg
    • Tank Type: Any

    TM Aquatix Aquarium Sand

    Perfect for decoration as well as using as a planting medium, this sand is nice and fine to act as a gravel base or on its own.

    The price is good for how much you get, and with such a range of bag sizes, you can stock up on as much as you want.

    The sand is 100% natural, which is crucial for ensuring your fish’s environment isn’t affected. It’s not artificially coloured but is instead made up of fine natural quartz.


    • Does not influence water parameters
    • Fine and soft for all fish


    • Colours: Multiple
    • Bag Size: Multiple
    • Tank Type: Any

    Sakana White Aquatic Fish Gravel

    A huge 10L tub if you have a lot of tank to fill, but it is also available in some smaller tubs if needed. In kilograms, this works out as double so is 20kg.

    It is bright, natural and decorative to really add a touch of class to your display. Non-toxic, it won’t damage the water pH levels or make it cloudy. Once it has had its initial clean, it will remain dust-free. 

    Each stone has a diameter between 3 and 8mm, making it safe for use with pretty much all fish breeds. It’s 100% natural, with no chemicals which can harm your fish, and it can also be used in outdoor ponds.


    • Indoor or outdoor
    • Good price


    • Colours: White
    • Bag Size: 1L, 2.5L, 5L, 10L
    • Tank Type: Any

    Buying Guide

    How we selected the best aquarium substrate

    We understand that there are various forms of substrates and you may have personal preferences or requirements. Therefore, we decided to try and find the best of the variations.

    To do this, we searched through thousands of reviews to find substrates that were rated highly and which were deemed safe for the fish. We immediately disregarded any with several negative reviews and any without enough reviews to really make a decision on.

    There are also substrates available that aren’t safe for fish in terms of the size of the pebbles, and others make the water cloudy. These were also left out of reviews.

    Types of aquarium substrate


    Often between 2mm and 5mm in size, gravel is usually a go-to. It is available in several materials and colours, meaning you can opt for the look you’re after.

    We think it is a better pick than pebbles. Firstly, any waste or old food should sit on the surface as the gaps in between every stone aren’t large enough to trap it, making it easier to clean. And it is more natural, allowing fish to burrow if required.


    Generally, the largest substrate and they come in a range of sizes. The materials can differ too, from stone and quartz to glass or plastic. Because they can be large in size, it leaves a lot of gaps in between each stone. This can cause dirt to build up, so they need to be cleaned regularly.

    Some fish can also struggle to bury in pebble substrate, and plants can find it hard to root in pebbles because of the gaps. Gravel is often better unless it is purely decorative and you’re happy to regularly clean them.


    Just like the sand on beaches, aquarium sand is again available in different sizes and coarseness levels. There are also colour variations available.

    It is one of the most natural options as most fish will be from an environment with sand or silt on the base of the water. There are no gaps between the grains to allow dirt to bury into the surface, so it is easy to clean. It can be messy if you’re doing a full tank clean, however, but this isn’t frequent.


    Of course, soil and water make mud and dirt – not ideal for a fish tank.

    So, the soil used for fish tanks is different. Soil is used in planted tanks, with live plants. If you don’t have any of these, you don’t need soil. Substrate soil will not mix with water, so is clean to use, but you may need something like gravel too if your fish like to bury.

    Water-changing substrates

    All of the substrates above are inert, and will not change the water when at the bottom of your tank. However, if you need your substrate to change the pH level of your water, soften it or release nutrients for plants, look into aragonite, peat or vermiculate.

    Other Buyers Ask...

    What is the purpose of aquarium tank substrate?

    You can have a tank without substrate, but having something in the base is much more natural. There are several reasons why your tanks should have a layer of substrate on the base.

    Tank cleanliness

    For many, it offers a place for any waste or uneaten food particles to settle and become captured, until the time comes for them to be cleaned up. This prevents them from breaking down as much and making the water cloudy or full of ammonia.

    Something like gravel also acts as a natural bacteria medium, encouraging the production and growth of ‘good’ bacteria which will help your tank filter out when cleaning the water. This bacteria can also help your plants to thrive, which boosts the life of your tank.

    Fish environment

    Some fish are benthic, so they naturally go along the bottom of the tank floor finding waste and food. Catfish and goby are two commonly found bottom-feeders in home aquariums.

    Breeds such as jawfish like having a sandy surface to dig into and hide or ‘hunt’. This burrowing can help them to feel safe, and the substrate also doesn’t reflect the image of the other fish in the tank as glass does, so they can stay hidden.


    Of course, the substrate can be aesthetic too. You can choose the colours, styles, sizes and material type if you want your tank to have a certain look, as long as your fish will be happy with it.

    When combined with plants, hiding places, rocks and driftwood, it creates a natural mini ocean environment. A well-crafted aquarium also is said to have a positive health benefit on those who gaze at it.

    How much substrate should I use?

    It is a good idea to use an exact calculator to work out your precise amount based on the size of the tank, your fish and how many fish are in the tank.

    Be aware that too much gravel or pebbles (with spaces in between) can cause too many anaerobic zones, which affect the chemical build of your tank.

    How often will I need to replace aquarium substrate?

    You can’t really change the gravel in your tank every year to alter the style and colour as you would paint your living room, change your curtains or get a new set of saucepans.

    This is the environment of your fish, plus it is a lot of hard work to do this. Gravel helps act as a biological medium, for the promotion of healthy bacteria which in turn helps oxygenate the water and keep it all clean. When replacing this, you’d have to try and maintain this all which is difficult and requires a few days.

    Vacuuming it and washing sections occasionally with a dedicated gravel cleaner should be enough to keep it clean. Purchase high-quality gravel and it should remain intact and looking good for years to come.

    Which substrate can I use for plants?

    Remember that the fish are your priority, but you do want something which works for both living things.

    Soil is often best if you want to promote growth in plants, however, you may need something like gravel to weigh them down and be suitable for the fish to bury in. Gravel is great as it keeps the roots of the plant tight enough to stay put, unlike stones or pebbles.

    Can I just use garden pebbles or gravel?

    No! You must buy a substrate specifically used for fish, which is clean and neutral in pH. Don’t just go out to the garden and collect spare stones, or go to B&Q and buy what you’d use on a garden path. This could cause upset in the tank and dirty water.

    Do I need to wash the substrate before putting it into the tank?

    Most aquarium substrate for fish is prewashed (hence why you can’t just buy some from a hardware store). However, you may still want to prewash it as it can get dusty in transit. Small particles which can be separated may not settle in water.

    You can place the substrate in a bucket and rinse by gently swirling, or put it in a sieve and rinse with a hose. You’ll never clean it completely, but once it has settled in the tank it shouldn’t cause too much upset to the water.

    Can I buy coloured gravel for a fish tank?

    It is readily available and could look great if you want an eyecatching display. However, just double-check the material of any coloured gravel before buying. Some are made from white dolomite, which is rich in calcium and magnesium and used to increase pH, alkalinity or water hardness.

    If your fish don’t like this, or if your water is already struggling to be maintained, be aware.

    Some people would argue that coloured gravel does not imitate a fish’s natural habitat and should be avoided, but fish are adaptable and there is nothing to prove it has a detrimental effect. However, we do have to say that a neutral coloured tank can a) make fish easier to spot and b) make the colours on fish really pop!