There are many types of aquarium substrate available, including rock, sand, pebbles, gravel, and even soil.
Each type has its pros and cons, so make sure you choose the right one for your betta.
I’ve tested different types of aquarium substrates over the years, and I’m going to share with you my top picks for betta aquariums.
In this article, I’ll look at the best substrates for bettas and how to choose the best substrate for your betta fish.
I’ll also compare each one’s pros and cons so you can decide which one works best for you.
Why do we use substrate in a betta fish tank?
There are many reasons why you should use substrate in a betta fish tank.
However, in this post, I shall focus on four main reasons why your betta fish tank should have substrate – Biological filtration, stable water conditions, stress reduction, and for aesthetics.
Substrate helps with biological filtration
Substrates are used in aquariums because they help keep the water clean and healthy.
When substrates are placed in tanks, beneficial bacteria colonize them and break down waste material. This process helps remove ammonia and nitrite from the tank water.
Beneficial bacteria are naturally occurring organisms found in soil, plants, water column, and on surfaces inside your tank.
With substrate, you provide more surface area for beneficial bacteria to colonise. More beneficial bacteria are good as it keeps ammonia and nitrite at bay for your bettas to stay healthy.
Substrates help achieve the pH you need and keeps it stable
Bettas need a stable pH level (pH) in order to live long healthy lives. Bettas are very sensitive to fluctuations in pH, and any change in pH can cause stress and illness.
If you’re not familiar with pH, here’s a quick primer:
pH stands for ‘potential hydrogen’. The lower the number, the more acidic the water. Water with a pH below 7 is considered acidic; above 7 is alkaline.
Most aquariums use tap water, which can differ from household to household. However, bettas prefer slightly acidic water, usually between 6.0 and 7.0.
Some species of wild bettas originate from peat swamps which might have a pH level as low as 3.0 to 4.0.
These fish require special care because if you don’t keep them in the range of pH needed, they are prone to disease.
So if you have wild bettas that require low pH, certain soil substrates can help you achieve these pH levels.
However, what’s most important is the stability of the pH level. With soil substrates, they will usually act as a buffer and keep your pH levels stable and consistent.
It’s important to note that not all substrates have buffering capabilities. So if this is what you need, look for an active substrate instead of an inert one.
Reduces stress on your bettas
Without any substrate, your betta is staring at an empty base. Substrates create a sense of bottom for your bettas.
Thus, with substrates, your bettas will feel safe knowing that there is nothing else below them except for… substrate.
You’d be surprised to know how much stress you might cause to a betta without any substrates. I’ve seen betta fish trying to swim below the base of the tanks they’re in or even try to fight the reflections of themselves that they see below.
So if you want a calm betta, add substrate to your betta fish aquariums.
Substrates make your tank (and betta) look nice
A bit superficial I know, but imagine looking at an empty tank – it gets kinda boring. With substrate, you add elements to your tank and it helps create some depth.
Even a bare tank with just substrate looks nicer and more interesting than an aquarium without.
But substrates don’t just make your aquarium look nice, it makes your betta fish look nicer too.
If you choose the right substrate and the right colours, you might enhance the colour of your betta fish.
With lighter substrates, it tends to wash out certain colours. Dark substrates enhance the colour of your bettas.
You may think it’s just due to the contrast, but I’ve kept wild bettas (which are dull in colour) in empty tanks, tanks with light aquarium sand, and tanks with dark soil.
They almost always showcase their brightest colours in tanks with the darker substrate. So I definitely believe it’s not just the colour contrast.
How much substrate do you need for a betta tank?
To be honest, 1 to 2cm (0.4 to 0.8 inches) of substrate is enough if you’re just adding some stones, driftwood, and attaching lithophytes plants (plants that can be attached to rocks and wood).
But if you’re planning to have a planted betta tank or looking to do some aquascaping, you’ll probably need quite a bit of substrate.
In smaller aquariums (30cm/1ft or less), you can get away with about 2.5cm (1 inch) thickness of substrate at the front and slope it up backwards with up to 5cm (2 inches) at the back.
This should give you just enough to plant your plants and provide some depth.
In larger aquariums or if you’re planning to plant heavily, you should go with minimally 5cm (2 inches) of substrate all around and you may slope it to the back should you wish.
This provides sufficient depth for the roots to grow in and for beneficial bacteria to colonise.
How do betta fish live in nature? What substrate do they have?
Great question! Many seem to think that bettas only originate from countries like Vietnam, Laos, Cambodia, and Thailand – living in rice paddies, ditches, and ponds.
However, that’s only partially correct. In my post about the wild betta natural habitat, I covered the different countries and habitats that they live in.
To summarise, the more popular varieties of bettas live in rice paddies, ditches, and ponds in countries such as Vietnam, Cambodia, Thailand, and Laos.
However, even more species of wild bettas come from Malaysia, Indonesia, and Singapore – and they live in places such as streams, peat swamps, and forest swamps.
So the substrate in these places definitely varies across which habitats you’re trying to replicate.
If you’re trying to build a rice paddy biotope, you’ll find that the substrates in those areas are muddy. I mean… they’ve got to use soil to grow rice right?
In peat swamps, it depends on the area, but bettas have been found to live in peat swamps with sandy or muddy substrates with a thick layer of leaf litter on top.
So if you’re trying to replicate this, it doesn’t really matter if it’s aquarium sand or soil. If you need something to buffer the water, the soil is for you. However, if you have other buffering agents, such as peat in your filters, then using sand as your substrate may save you some money.
Lastly, for bettas found in streams in the wild, the substrate is usually light-medium dark (is this even the right word?) gravel or sand.
How to choose the best substrate for your betta?
As you may know by now, there are quite a few things you need to consider before choosing the best substrate for your betta.
Are you trying to replicate a biotope? Are you trying to start a planted tank? Or do you just want something that will enhance your betta’s colours?
Well, here are some of the things you should consider when wanting to select the best substrate for your betta tank.
Substrates for betta fish – Planted vs. Unplanted
I think one of the most important considerations you’ll need to think of. Since the aquarium will be in your home, what do you plan to showcase to yourself, your family, and your guests?
Do you want to build a planted tank for your betta fish or do you want to try building a Star Wars-themed tank?
If a planted tank is what you’re after, then you should consider using aquarium soil for your betta fish tank. Aquasoils provide nutrients necessary for your plants to thrive and also buffers the water.
Generally, most soils are acidic in nature, so you don’t have to worry about the pH levels so much (until the soil gets old ~2 years>).
But if you’re sparsely planting, using non-nutrient-demanding plants, or not using aquarium plants at all, then you can consider gravel substrates or sand. This way, you don’t have excess nutrients leeching into the water column that won’t be used up – causing algae issues – and you save some money.
If you realise that your plants need nutrients, then you can consider dosing aquarium liquid fertilisers and/or adding root tabs in your substrate.
What substrate do bettas live in, in nature?
Replicating where a betta comes from is one of the things you should consider first when choosing the best substrate.
What are you trying to replicate? Which biotope? Which is the natural substrate found there? Sand, gravel, or soil?
I’ve covered this earlier in the article, so scroll up to decide which you’ll need.
Buffering capabilities of your substrate
I think I’ve mentioned this quite often in this post. If you need a substrate that can buffer your water and make it more acidic, aquasoil is something you should consider.
If not, you’ll need to find other ways such as adding peat in the filter, using botanicals, or using chemical pH buffers.
But how would you know if you need a substrate that can make your water acidic?
The very first thing to check is to understand what species of betta you’re keeping. If you’re keeping the domestic betta splenden, then they are pretty hardy and tolerant of a range of water conditions.
I’ve even heard of people keeping and breeding them in waters with a pH of 7.5!
In fact, even if it’s a wild betta – let’s say the betta albimarginata – has been kept in higher pH levels from the breeder or from a previous hobbyist, you’d want to match that pH level as much as possible.
Even though the betta albimarginata have been found in waters with a pH between 4.0 to 6.5, if your breeder keeps them at pH 7.0, you should follow this as well.
That’s because the betta has been conditioned to live in higher pH levels and throwing them into a tank with pH 4.0 would shock and possibly kill them.
This is why acclimatising your livestock is important.
Now that doesn’t mean you should keep them at pH 7.0 continuously. You can try lowering the pH slowly by 0.1 points over multiple water changes until you reach the target pH. Always remember that the difference between pH 6.0 and pH 7.0 is that pH 6.0 is 10 times more acidic.
But if you’re getting a wild-caught wild betta, then you should try to replicate their habitats and slowly acclimate them to your tanks.
Alright, so I’ve answered what types of substrates you should use if you need buffering capabilities. But what if you’re not?
Then you can opt for inert substrates, such as inert sand or gravel. I’ll share more on this in the other types of substrates later on.
The thickness and size of the substrate
The thickness and size of the substrate is not a very important factor, but a factor you should consider nonetheless.
Are you keeping your betta in a small 30cm (1ft) tank or a large 90cm (3ft tank)?
This is where the thickness of the substrate matters.
In small tanks, opting for finer and thinner textures (such as sand or smaller gravel) will make your tank look bigger. So if you’re using smaller tanks, then finer ones will look better for your tank.
But how does this affect the betta?
Well apart from aesthetics, the thickness matters to the betta because of its fins. Thicker ones such as gravel tend to have sharp edges (apart from pebbles) that might tear the betta’s fins.
You don’t want your betta’s beautiful fins to be torn by something that could be prevented, do you?
So if you want to use a thicker or bigger substrate, make sure that it’s rounded.
Colour of the substrate matters for your betta
The last consideration when selecting the best substrate for betta tanks will definitely be its colour.
Generally, bettas in the wild prefer to live in darkness – that means the lighting, water column, and substrate – to hide from predators.
Many hobbyists also prefer to keep their wild bettas with dark-coloured substrate as it brings out the colours of their bettas.
So this means you should consider opting for black sand/gravel/soil if you want the colours to pop out.
If trying to replicate the biotope, then you have to consider using tan substrates, such as sand or soil.
Personally, I’ve used tan sand for my substrate and it still brought out the colours of my domestic betta splenden, betta albimarginata, and betta mahachai.
As much as I want to put them in tanks with a dark substrate, dark water, and low light, I still want to have a nice-looking tank to showcase to my family and my guests. So, I had to compromise a little.
But that didn’t wash out the colours of my bettas though.
I think the most important factor is to use dim lighting, have a black background, and add some tannins to your water.
Even with a light substrate, my bettas’ scales were iridescent and they were beautiful, nonetheless.
So the colour of the substrate – is up to you. Just try to use more natural colours.
Is gravel, sand, or soil better for an aquarium?
There is a wide variety of substrates, but the three main types of substrates used in aquariums are gravel, sand, and soil. Each type has advantages and disadvantages, so choosing the correct one depends on your needs.
Gravel is usually recommended for beginners who just want to set up a tank. It provides plenty of space for water to flow through, making it easy to clean and maintain. While it does require frequent maintenance, it’s inexpensive and easy to replace.
Sand is ideal for experienced hobbyists who want to create a naturalistic environment. It allows aquarium plants and animals to thrive while still giving the illusion of nature. Sand is also easier to clean than gravel as uneaten food can be seen easily, but it requires more care and attention.
Soil is perfect for advanced hobbyists who want to build a complex ecosystem. It provides nutrients for your plants while also making the water acidic. Like sand, it takes extra effort to maintain, but it’s worth the trouble.
While each type of substrate has its own benefits, they all share one thing in common: they’re all fine for your bettas. As previously mentioned, it depends on what your needs are and what you’re trying to build.
Don’t worry too much about it, really.
Using a mix of substrates for your aquarium
If you’re feeling adventurous, you can opt to have a mixture for your substrate. If you need aquasoil in your tank, you can use it as a base layer and then top it off with sand or gravel!
This way you can provide nutrients while maintaining the pH levels of your tank.
Or perhaps you want to have a mixture of sand and gravel? You can mix them with varying proportions and it’ll give different results.
Mix and match the colours and the texture of both to get the desired outcome you’re looking for.
Mixing substrates is something that many hobbyists do to obtain more natural-looking aquariums.
What other types of substrates are there?
Many beginner hobbyists use aquarium marbles in their aquariums for aesthetic reasons. However, marbles are reflective which your bettas might not like.
If you’re keeping wild bettas, try not to use marbles as they might wash out their colours.
As marbles are pretty big as well, uneaten food might be trapped in between them which will affect your water parameters.
Unless you want to do constant vacuuming of your gravel, marbles are a bad choice of substrate.
Natural stones (River Stones, Stone Aggregate, Marble Chippings)
You may be considering adding stones and rocks into your aquarium, or you might want a whole substrate made out of stones.
Can you do this for your betta aquariums?
Sure you can. You can select stones with both artificial colours and natural colours – entirely up to you. You can also select stones with different sizes, just be careful when choosing your stones as those with sharp edges might rip your bettas’ fins.
Also, you need to make sure the stones you’re adding to your betta fish tanks are inert. This is important as stones tend to contain calcium carbonate that will alter your water chemistry.
Unlike aquarium soils, stones tend to make your water more alkaline, which is something bettas generally do not like.
How do you know if they’re inert or won’t raise your pH levels? Pour some vinegar on your rocks. If they’re bubbling, they will affect your water chemistry.
If they don’t bubble, then they won’t.
Coral sand is a type of aquarium sand you should avoid using for your betta fish tank. Why? Coral sand contains coral – usually meant for marine tanks and not for a freshwater aquarium – which will affect your water parameters by increasing the pH levels.
Because of this, coral sand is not the ideal substrate to use for your betta fish tanks.
However, some brands market their sand as coral/marine sand. Despite this, they are inert and won’t affect your water parameters.
So if sand is your choice of substrate, you might wanna do a bit of research on whether the aquarium sand is inert or not.
Most will put it on the bag of the substrate, but for some, you have to research online.
No substrate can also be your choice of substrate. You can add botanicals and leaf litter to your betta aquariums and you can call it a day.
With a thick enough layer of leaf litter, it’ll still look like a betta’s natural environment. However, it will be harder to maintain your water parameters due to the amount of botanicals you’re adding.
Also, if there are too much botanicals, the rotting leaf litter will affect your water quality and it can be difficult to keep your water clean.
Say you want a completely bare aquarium with nothing at the bottom, I guess it’s fine too, I believe your betta should get used to the environment after a while. You can easily see and remove any uneaten food that will keep the water clean and water parameters stable.
However, there will be lesser surface area for healthy bacteria to grow, so make sure you have good filtration in your tank.
Best Substrate for Planted Betta Fish Tank
ADA Amazonia Aqua Soil
The ADA Amazonia Aqua Soil is one of the most famous aquarium soils used by hobbyists in Asia. It’s rounded, so it won’t have any sharp edges that might potentially hurt your bettas.
This is marketed as soil for planted tanks – and this active substrate is potent. Immediately when you start filling your aquarium with water, you’ll notice a large ammonia spike.
So if you’re using this, make sure to cycle your tank for a few weeks first to establish a colony of beneficial bacteria. Plant heavily from the start so that your aquatic plants can have time to establish their roots and absorb all the essential nutrients.
Its dark black colour brings out the colours of your bettas and the aquatic plants you’re trying to grow.
Furthermore, this will affect your water parameters. It’s been reported to bring pH levels down to 4.5 but will stabilise around 5.5 – 6.0 after a while.
Oh, this can be used for small aquariums or larger tanks but will be better for larger aquariums as the granules can be pretty big.
They have a powder version which costs almost twice the amount, but if you don’t mind the larger granules, they’ll work fine for smaller tanks too.
Thus, if you need something to make your water acidic or want to start a planted tank for your bettas, this is the option for you.
The Fluval Bio-Stratum is the perfect choice for you if you’re looking to slightly buffer your water, need more biological filtration, and looking to grow aquatic plants.
The Fluval Bio-Stratum has been reported to bring down your pH levels anywhere between 6.0 – 7.0, which is perfect for most bettas.
Unlike the Fluval Stratum, the Fluval Bio-Stratum is made up of beneficial “bioactives” that are porous, providing beneficial bacteria with more surface area to colonise.
Take note that the Fluval Bio-Stratum will leech out ammonia at the beginning, so you’ll need to test your waters to make sure that your water parameters are alright.
It’s also black in colour, making it an excellent choice if you’re trying to make the colours of your bettas pop!
Seachem Flourite Black Sand
The Seachem Flourite Black Sand is a great choice if you’re looking for a dark-coloured sand substrate. Although this is marketed as sand, it’s not actually sand but porous clay that is so fine that it’s the size of sand.
Due to its porous nature, it acts like an additional biological filter due to more surface areas for bacteria to colonise.
This sand is inert and can be used to grow aquatic plants, but you’ll need to supplement them with liquid fertilisers or root tabs.
Take note that because it is inert, it will not affect your water parameters, so you’ll need to find other ways to reduce the pH levels.
The Seachem Flourite Black Sand comes pre-washed but with all aquarium substrates (except for aquarium soil), you should rinse them first to prevent your water column from clouding.
CaribSea Super Naturals Aquarium Sand
The CaribSea Super Naturals Aquarium Sand is a good substrate for betta fish if you’re looking to add more colours to your tank.
I prefer the sunset gold colour as it looks like natural sand as compared to their crystal river sand, which is pretty bright white.
This sand is inert and won’t affect your aquarium water conditions – so you need to reduce the pH levels via other means.
It’s also relatively affordable as compared to previous options, so if budget is a concern, opt for this too.
Take note that this is very dusty and will cloud your water. Rinse it until it runs clear before adding it to your aquariums.
CaribSea SuperNaturals Peace River
Another option from CaribSea, this time their SuperNaturals Peace River aquarium gravel meant for both marine and freshwater tanks. This is natural gravel with a mixture of white, light brown, brown, and black gravel
However, in the aquarium, it’ll look moderately brown, perfect for the river look.
This aquarium gravel is inert and will not affect pH levels, so again you’ll need an acidic buffer. It isn’t an active substrate so if you’re growing plants, you might need to supplement them with essential nutrients from other sources.
Similar to the CaribSea Natural Sand, you will need to rinse this multiple times as it will make your water dirty.
In conclusion, the substrate that you choose for your betta fish depends entirely upon what type of tank you plan on using.
For example, if you want to use a planted aquarium, you’ll probably want to opt for aquasoil instead of sand or gravel because plants require the nutrients it provides.
On the other hand, if you’re planning on using a biotope tank, you’ll definitely want to consider sand or gravel as certain habitats have these as their substrate.
The bottom line is that choosing the right substrate for your betta fish can be said to be essential to their overall happiness.
And I hope this post has helped you in selecting the best substrate for bettas.
Let me know what you think in the comments down below!