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The Best Substrate For Betta Fish: Natural, Themed & Planted Tanks

Choosing the right substrate for your betta tank can have an impact on the health of your fish and your aquarium. So let’s look at how to choose the best substrate for betta fish!

By Matt Thomas
Last updated on

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best substrate for betta fish

When it comes to setting up your betta’s tank your choice of substrate is not just about aesthetics, it can also impact the health of your aquarium and your fish. So how do you choose the best substrate for betta fish?

We’ve looked at some of the best substrates for betta fish across a range of scenarios. If you want a live-planted tank, Seachem Flourite provides the right nutrients without affecting water parameters. Or for a natural gravel look, Spectrastone Premium Gravel is a perfect choice.

And we’ve also covered a range of other substrates too. From sand to fine and coarse grain gravels, you’ll find all you need to choose the best substrate for your betta fish!

So let’s take a look at the list…

  1. Best For Live Plants: Seachem Flourite
  2. Best Natural Look Gravel: Spectrastone Premium Gravel
  3. Best Fine Sand: CaribSea Super Naturals Aquarium Sand
  4. Best River Stone: Sackorange Aquarium Gravel River Rock
  5. Best Fine Gravel: CaribSea Super Naturals Peace River
  6. Best Colored Gravel: Imagitarium Blue Jean Aquarium Gravel

Best Substrate For Betta Fish Reviewed

We’ve assessed some of the best substrates for betta fish based on key factors including suitability for your fish and your water parameters. So whether you want to start a live planted tank for your betta, or want easy-to-maintain aquarium gravel you’ll find all you need below.

1. Seachem Flourite

Photo: Amazon.com

  • Substrate Type: Clay gravel
  • Bag Weight: 15.4 lbs
  • Color: Brown/ natural
  • Key Features: Supports planted tanks, natural porous clay, no modifiers like laterite needed, not chemically coated, pH neutral
  • Best For: Live plants

Flourite is a porous clay gravel and works to absorb nutrients from your water including plant fertilizers, making it very efficient at providing them to your plant’s roots. It’s also a great surface for beneficial bacteria to colonize helping keep ammonia and other water parameters in check.

Unlike active plant substrates, which contain organic acids designed to lower the pH, Flourite is an inert substrate with no chemical coatings and so won’t change your pH or other water parameters. This is key for your betta which needs a fairly neutral pH between 6.5 and 7.5.

Some planted tank substrates need to be used with an additional modifier layer underneath, like the iron-rich clay laterite, to provide additional nutrients. But as Flourite is so good at absorbing and storing them you won’t need to use a modifier.

Many plant substrates are made up of nutrient-rich soil compressed into pellets. This helps them release nutrients slowly but eventually, they’ll break back down into silt. As Flourite is clay-based gravel it won’t break down, so you’ll never need to clean out and replace it.

As Flourite is quite light and flat, you’re likely to need to use more than you would with other aquarium gravel to get a good 2-inch layer. But the 15.4 lbs bag provides more than enough for a 5 gallon betta tank.

Note as Flourite is clay-based it is incredibly dusty when you receive it and must be rinsed thoroughly. We recommend you rinse 3 or 4 times with a 5 gallon bucket of water, always add it to an empty tank, and carefully add water a little at a time to minimize clouding.

2. Spectrastone Premium Gravel

Photo: Amazon.com

  • Substrate Type: Natural gravel
  • Bag Weight: 5.0 lbs
  • Color: Natural stone mixed color (including yellows, reds, and grays)
  • Key Features: Inert natural stone gravel, plant-based polymer coating, will not affect pH, various small size grains (approx. 2mm to 4mm)
  • Best For: Natural look gravel

Spectrastone Premium Gravel is a great choice if you want a natural look. Its small mixed-size grains, from around 2mm to 4mm, are large enough to be safe with many filters and also give the appearance of a natural stream bed.

Note that while the 5 lbs bag would usually be plenty to provide a 1-inch layer in a 5 gallon betta tank because the particle size is smaller, we recommend 2 bags for a nice even coverage.

But as the grain size is smaller than other gravels, waste food and feces tend to sit on the surface making your weekly vacuum easier. Although particles will still get into the substrate over time so make sure you vacuum right to the bottom every 2 weeks.

Spectrastone Premium Gravel is coated with a plant-based polymer sealing it to stop minerals from entering your water and changing the pH. As this means it’s inert you can be confident it won’t affect the neutral pH your betta prefers.

We found this gravel to be a good anchor for betta-friendly rooted plants like Cryptocoryne, but bear in mind it won’t provide any nutrients for live plants like Flourite will. Overall many users praise this gravel for its natural look but note it needs plenty of rinsing before use.

3. CaribSea Super Naturals Aquarium Sand

Photo: Amazon.com

  • Substrate Type: Natural fine sand
  • Bag Weight: 20.0 lbs
  • Color: Natural
  • Key Features: Inert/ pH neutral, no artificial paints or dyes, grain size reduces build-up of waste, includes BioMagnet clarifier
  • Best For: Fine sand

CaribSea Super Naturals Aquarium Sand is one of the best substrates for betta fish if you prefer the appearance of sand over gravel. It has a natural stone color without using dyes or paints, so it’s completely inert and won’t affect the neutral pH your betta needs.

The small, soft grains are about the size of sugar crystals and won’t cause damage to your betta’s delicate fins or tail. And because the sand compacts down, waste tends to stay on the surface making it much easier to clean with your aquarium vacuum.

As with any substrate you’ll need to rinse the sand before use, but we found it sits well at the bottom with no floating dust particles. But make sure you position your filter intake a few inches away from the surface and protect with filter sponge to avoid any sand being sucked up.

Whilst this sand doesn’t provide nutrients for live root-feeding plants, many users have had success using fertilizers such as root tabs. But also note, that as the grains can compact down it can be difficult for plants to spread their roots.

Make sure to gently swirl your sand every few weeks to prevent any unoxygenated areas that may allow hydrogen sulfide to build up as this can harm your betta. But overall many betta owners praise the soft texture and beautiful natural look this sand provides.

4. Sackorange Aquarium Gravel River Rock

Photo: Amazon.com

  • Substrate Type: Natural river stone/ pebbles
  • Bag Weight: 2.0 lbs
  • Color: Natural pebble mix including black, white, yellow, and red shades
  • Key Features: Polished natural gravel, varying sizes with largest pebbles around 1 inch, inert with no chemical coating
  • Best For: River stone

Natural river stones and pebbles can be a fantastic addition to your betta tank when used alongside gravel. These pebbles from Sackorange provide the perfect highlight to give your betta’s tank a natural river bed look.

At 2.0 lbs, the bag is quite small and certainly would not be enough for a 5 gallon tank if you were to use it as the main substrate. But when combining it with gravel as a finishing touch there’s more than enough.

We don’t recommend using it as your main substrate though as due to the large size of the pebbles (up to around 1 inch), waste and live food can easily get trapped within the layer making cleaning difficult. And inadequate cleaning could cause ammonia levels to rise.

The stones are polished, smooth, and round so won’t cause damage to your betta. But do still check for any sharper stones that may be present before using in your tank. They are also inert with no chemical coating so won’t affect the neutral pH your betta prefers.

Overall several owners praise these river stones for giving their tank a natural look and for their smoothness making them safe for use with their betta.

5. CaribSea Super Naturals Peace River

Photo: Amazon.com

  • Substrate Type: Natural gravel
  • Bag Weight: 5.0 lbs
  • Color: Dark natural mix including gray, white, black, and brown shades
  • Key Features: Polished natural gravel, small uniform size (approx. 2mm), no chemical coating, pH neutral – will not increase carbonate hardness, includes 5 gallon dose of BioMagnet clarifier
  • Best For: Fine gravel

If you want to give your betta’s aquarium a natural look without the coarseness of some other gravel CaribSea Super Naturals Peace River is a great option. Its uniform grain size of about 2mm gives a smooth look almost like sand.

The grains are large enough for oxygenated water to move between them but small enough that they compact down so food and other waste sit on the surface. This makes cleaning easy as you’ll only need to vacuum on top of the layer with an occasional deeper clean below.

The gravel is cleaned and polished before packaging, and has no chemical coatings so is pH neutral and won’t increase carbonate hardness (kH) [1]. So you can be confident you won’t increase alkalinity or change the neutral pH in your tank that your betta needs.

The 5.0 lbs bag is about the right size for creating a 1-inch layer in a 5 gallon betta tank, but if you want more depth for live plants you’ll need another bag. Also bear in mind this substrate does not provide additional nutrients for live plants so you may need additional fertilizer.

Super Naturals Peace River also comes with a 5 gallon dose of BioMagnet clarifier. Simply add it to your tank when you set it up and it will encourage particles in your water to clump together turning it from cloudy to crystal clear.

6. Imagitarium Blue Jean Aquarium Gravel

Photo: Amazon.com

  • Substrate Type: Artificial gravel
  • Bag Weight: 5.0 lbs
  • Color: Mixed dark and light blues, and teal shades (other colors available)
  • Key Features: Non-toxic fish-safe painted gravel, varied size (approx. 3mm to 6mm)
  • Best For: Colored gravel

If you prefer colored gravel in your betta’s tank over a natural look, Petco’s Imagitarium Blue Jean Aquarium Gravel will give it a beautiful teal blue base. Imagitarium gravel is also available in a range of other colors depending on what suits you.

The gravel is painted with non-toxic fish-safe paint and so won’t affect pH or other water parameters, so you can maintain a neutral pH for your betta. And the coating is also designed to allow beneficial bacteria to colonize, supporting your tank’s nitrogen cycle.

This gravel is coarser than some of the others we’ve featured. With a varying grain size of about 3mm to 6mm, it means you can use it with most filters, including undergravel filters, without worrying about it being sucked up. 

We found the 5.0 lbs bag provides just under a 1-inch layer at the bottom of a 5 gallon betta tank, so if you want better coverage to anchor plants it’s worth buying the extra bag or larger size. And do make sure to rinse before adding to your tank to remove any dust.

While some users have found the paint can chip in places they’ve also highlighted it’s hardly noticeable, and if you handle it carefully when adding to your tank it shouldn’t occur. Overall most users praise this gravel for its ease of cleaning along with its beautiful color.

Considerations When Looking For The Best Substrate For Betta Fish

The importance of choosing the best substrate for betta fish can often be overlooked when it comes to setting up your betta’s tank. Along with choosing the best decorations, getting the substrate right can greatly affect your betta’s environment.

blue betta on black substrate

Why Is Substrate Important In Your Betta Tank?

Choosing the best substrate for your betta fish has a number of benefits. Not only can it make your betta tank look good, but it helps anchor plants in place, and can even stop your betta from acting aggressively against its own reflection in the bottom of your aquarium [2].

But there are some other important considerations that may be less obvious.

What Substrate Does A Betta’s Wild Environment Have?

Betta fish are native to streams, ponds, and rice paddies of South East Asia where the water tends to be slow moving and full of vegetation. The bottom of these habitats often has a thick deposit of mud, leaves, and other vegetation.

Because of this decomposing matter, the water conditions can fluctuate from a neutral pH of 7.0 to acidic at times, even down to around pH 5.47 [3]. Bettas can adapt to these fluctuations, and studies have shown a pH drop from 7.4 to 5.5 to have no impact on their growth [4].

Water Chemistry And pH Balance

But when it comes to your betta’s tank at home, your water should have a fairly neutral pH, within the range of about 6.5 to 7.5. This means when it comes to the best substrate for betta fish, you’ll generally want to choose an inert substrate that doesn’t alter the pH.

Inert vs Active Substrate

Inert substrates are chemically inactive and won’t change your pH or other water parameters like KH (carbonate hardness) or GH (general hardness). These are the best substrate for betta fish, and there are plenty of types of inert sands, gravel, and natural stones to choose from.

Active substrates are designed to change your water parameters, often to lower the pH for use in planted tanks. Look to avoid active substrates for your betta fish so that you don’t alter the chemistry of your water.

Biological Filtration And Beneficial Bacteria

While your aquarium should have the right betta filter to keep the water clean, carefully choosing the best substrate for your betta fish can also help with biological filtration.

This type of filtration involves beneficial nitrifying and denitrifying bacteria breaking down harmful ammonia in your betta’s tank via the nitrogen cycle. These beneficial bacteria not only colonize biological media in your filter but can also live and thrive on the right substrate.

Types Of Betta Tank Substrate

There are several types of substrate suitable for your betta, but choosing the best substrate for your betta fish can depend on factors such as tank size and whether you plan to keep live or artificial plants.

Overall we recommend aquarium gravel as one of the best substrates for betta fish. Check out the below to find out why, along with all the information you need on other types of substrate.

Aquarium Gravel

One of the best substrates for betta fish tanks is undoubtedly gravel. It’s also one of the most common given its wide range of colors, allowing you to give your tank either a colorful or a more natural look.

As gravel is made up of heavier particles than sand, it will sit well on the bottom of your betta’s tank without being stirred up by your fish or being sucked into the filter. It’s also easy to clean with your aquarium vacuum and provides a great surface for beneficial bacteria to colonize.

If you do go for gravel, make sure it’s smooth with no sharp edges that could damage your betta’s fins. High-quality aquarium gravels will usually specify that they use smooth grains on the packaging.

Aquarium Sand

The common alternative to gravel in betta tanks is aquarium sand. As sand particles are very small it makes this substrate quite compact. This means any feces and uneaten food sit on the surface, making it easy to clean with your vacuum.

Again, aquarium sand comes in a variety of types and colors so you can easily create a fantasy-themed betta tank or a natural look. And there are obviously no sharp edges, making sand one of the best substrates for betta fish when it comes to their delicate fins.

If you do use sand you should gently swirl it at least every two weeks, particularly under rocks or where it’s poorly oxygenated. In a similar way to ponds, anaerobic bacteria can establish in these areas and produce hydrogen sulfide, turning your sand black [5].

Whilst hydrogen sulfide can be toxic to your betta, and many aquarists will highlight the importance of swirling your sand, in reality, you are unlikely to have an issue in a 5 gallon betta tank as long as you keep it clean and well maintained.

Natural Stone And Aggregate

We often recommend natural stone to use alongside gravel rather than on its own. Stone aggregate is much larger and made up of pebbles and stones from natural sources like streams or rivers.

You can create a great natural look by using aggregate along with gravel, but as the stones are often large (around 1 inch or over) if you use them as your only substrate it can make the bottom of your tank difficult to vacuum, and live food can easily hide and get lost within it.

Ensure that you only ever purchase aquarium stone that has been properly treated. Never use stones you find yourself as they may have sharp edges, can alter the pH and chemistry of your water, and can also bring in bacteria or parasites that could cause disease.

Aquarium Marbles

If you want a colorful and striking look, aquarium marbles can be a good choice in a smaller betta tank. As each marble is flat and large, often around 0.5 to 0.8 inches, they can be difficult to vacuum and food and debris can get trapped between them.

For this reason, you need to ensure you keep up with your water changes around every 1 to 2 weeks to keep ammonia and other water parameters in check. So they are much better for a 5 gallon tank rather than a larger aquarium where upkeep is more difficult.

No Substrate

Having a bare-bottomed tank is an option in some cases, but we wouldn’t recommend it for most betta tanks. It’s certainly easy to clean and can be useful if you are breeding bettas as you can easily spot and monitor the baby fry.

But the main problem is a lack of substrate means less surface area for beneficial bacteria to colonize. And while your filter does a lot of the biological filtration, the substrate acts as a very important biofilter too [6].

Substrates To Avoid

There are a few types of substrate you should always avoid when it comes to your betta’s tank. Here are the main ones to look out for:

  • Coral Sand: With its coarse texture and large grains, coral sand is actually more like gravel. It’s a good substrate for saltwater aquariums or freshwater tanks if you need to raise the pH. But avoid this in your betta tank as you need a neutral or slightly acidic pH.
  • Play Sand Or Building Sand: As with any type of substrate, always avoid sand that isn’t specifically made for aquariums. Play or building sand can contain harmful bacteria that can lead to algal growth or disease in your betta.
  • Marble Chippings: Unlike glass marbles, marble chippings come from marble rock. While they look similar to some aquariums gravels they should be avoided as they contain calcium carbonate which will raise the pH of your water [7].

How to Choose The Best Substrate For Betta Fish

Having considered the importance of choosing the best substrate for betta fish, let’s take a look at the main factors to help with the decision when it comes to your betta’s tank.

blue betta on blue and purple gravel

Natural vs Fantasy Or Themed Tanks

Choosing the best substrate for betta fish in a natural tank depends on several factors. For example, gravel is often better than sand if you want a live-planted tank as it allows better circulation of nutrients.

It’s also possible to find clay-based gravel products that are inert. These have the advantage of giving a very natural look whilst not altering the pH of your water. You could also use a mix of gravel and larger stone aggregate to enhance the natural look.

When it comes to themed tanks there are many colorful sands and gravel options available but bear in mind that colored sand can fade quicker. It’s also best to choose gravel that has been sealed if you want to reduce color loss.

Think about which substrate will work with your filter too. If you own an undergravel filter, make sure you don’t use sand as it will cause it to clog. 

How Much Substrate Does Your Betta Tank Need?

Whether you’re using sand, gravel, or any other type of substrate in your betta’s tank the general rule is to add about 1 inch at the bottom. If you plan to grow live plants increase this to 2 inches. You can of course build up your substrate higher in places to give a more natural look.

When calculating how much substrate to use, many aquarists follow the rule of a pound of substrate for each gallon. So for a 5 gallon tank you’ll need about a 5 lb bag of substrate. But bear in mind sand is more compact than gravel so it can be more like 1.5 lbs per gallon.

If you own a larger betta tank over 30 gallons, perhaps as part of a community aquarium, this calculation tends to be around 1.5 to 2 lbs per gallon to get good coverage.

Choosing Substrate For Live Plants

Some of the best live plants for betta tanks, such as Anubais with its soft, broad leaves, use driftwood or other surfaces to anchor to. This makes your choice of substrate less important since these plants don’t actually use it. The same goes for floating plants like Pennywort.

But if you choose root feeders like Cryptocoryne or Amazon Sword you’ll need the right substrate. Some betta owners choose to use aquarium soil topped with gravel to give a good anchor and provide the right nutrients.

But in fact, clay-based gravels can be one of the best substrates for planted betta fish tanks. Unlike sand they are not too compact, so your plants can spread roots and pick up nutrients. And they are usually inert so will not alter the pH of the water for your betta.

Which Substrate Is Best For Cleaning?

Whichever substrate you choose for your betta tank regular maintenance and removal of excess food and waste every 1 to 2 weeks is key to ensuring excess ammonia doesn’t build up. 

But how difficult are the main types of substrate to clean and maintain?:

  • Gravel: Gravel can be one of the best substrates for betta fish tanks when it comes to cleaning. It’s compact enough that waste won’t penetrate into the layer and yet it allows water to circulate helping to keep the layer oxygenated.
  • Marbles & Natural Stone: These larger substrates can be the most difficult to clean as their size means waste can get deep into the substrate layer between the gaps.
  • Aquarium Sand: As sand is compact any waste sits on the surface making it easy to vacuum away. Just make sure you hold your aquarium vacuum about an inch above the surface so as only to suck up the waste and not the sand itself.

It’s worth also reiterating that if you do choose aquarium sand, as well as vacuuming you’ll need to gently swirl it every two weeks to stop dead areas forming which can allow harmful hydrogen sulfide to build up.

Our Verdict

Choosing the best substrate for betta fish can really depend on what you want to get out of your setup.

If you want to keep root-feeding plants, Seachem Fluorite is our recommended choice as it will provide the right nutrients without affecting your water parameters. Or for a natural look with easy-to-clean gravel, Spectrastone Premium Gravel is our preferred option.

But there are plenty of other top choices in the list above. So whether you want easy-to-maintain gravel or aesthetically pleasing natural sand, our guide will help make the right choice for you and your betta!

FAQs

We’ve answered some of the top frequently asked questions when it comes to choosing the best substrate for betta fish tanks. Take a look at the answers below.

Which Substrate Is Best For Bettas?

Aquarium gravel or clay-based gravel such as Seachem Fluorite can be the best substrate for betta fish as they don’t compact like sand and are inert so won’t alter the pH of your tank.

Is Sand Or Gravel Best For My Betta?

Either can be very suitable for betta tanks, but if you choose sand remember to swirl it gently every two weeks to prevent dead areas that may cause hydrogen sulfide to build up.

Can I Mix Substrates In My Betta Tank?

Yes. Mixing substrates such as gravel with some larger stone aggregate can help give a natural look while improving water circulation at the base of your tank.

Can I Choose To Have No Substrate In My Betta Tank?

This can work well if you are breeding your betta and want to keep an eye on the fry. But we don’t generally recommend it as it also means less surface area for beneficial bacteria.

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AUTHOR
Matt Thomas
Matt has been keeping fish since junior high when he used to look after his parent's tank. He loves guppies, cichlids, and his crowntail betta named Bobby.

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