Aquarium Substrate Guide For Bettas (FAQ)

Believe it or not, choosing a substrate for your tank is quite a big decision. It’s not as simple as going into PetSmart and grabbing what you see first. Different substrates are going to have different effects on your betta. But don’t worry, this aquarium substrate guide for bettas is going to make you an expert! And when you’re done reading it you can buy your substrate with confidence.

The Ultimate Aquarium Substrate Guide

You are going to have all your questions answered after reading this guide! So let’s get started, first of all…

What Is Aquarium Substrate?

Aquarium substrate is whatever you line the bottom of your fish tank with. A lot of people think it’s only there as decoration, or to make your tank look nice. But, in actual fact, it plays a more vital role than that. The type of substrate you use can affect a lot of things including how hardy or soft the water is, the pH of the water, and most importantly the well being of your betta.

What Is The Purpose Of Aquarium Substrate?

There are so many reasons to use an aquarium substrate.  Here are some of the best perks to using substrate in your bettas tank.

  • If you know anything about the nitrogen cycle then you know the importance of bacteria. Certain bacteria help break down nitrates, nitrites, nitrogen, and ammonia. All of which can be damaging to the health of your betta. Substrates are good because they house bacteria in them which allows the bacteria to thrive.
  • I think the main reason people use substrate is to make their tank look better. If you’re like me, you may think an empty glass floor looks barren and unnatural. And also an empty tank floor can stress your betta out. If too much light reflects off the glass your betta might start flaring up.
  • On the subject of aesthetics, substrates also help to make your betta’s colors pop. Especially if you use darker more natural substrate.
  • A substrate is also going to make your aquarium feel more natural to your betta. Think about what your bettas natural environment is like. It’s not a glass bottom floor, but rather gravel, soil, rocks or sand with a lot of plant life.
  • Obviously having plants in your tank is extremely important for a betta. They give your betta places to hide and make the tank feel more natural. And substrates help to anchor your plant in place.
  • Some substrates also help change the pH of your aquarium, make the water soft or hard, as well as absorbing detrimental substances and releasing beneficial ones.

What Substrate Are Bettas Used Too?

A good question you should ask yourself is what substrate is best for your betta? While you want your tank to appeal to you, remember it’s your bettas home. So you should actively try to use a substrate that is going to be best for them.

You probably know already that betta fish are often found in rice paddies, slow-moving streams, marshes, and drainage ditches.

The normal substrate here would be soil, mud, silt, and a LOT of vegetation. While this works great in the wild, it’s not going to be so great in your aquarium. Not only would the silt and soil constantly make the aquarium look murky, but it would become unhealthy for your betta over time.

Nature is a lot more efficient at keeping these sorts of environments habitable. So as long as you’re giving your betta plenty of plants to hide in, you have a bit of leeway with the substrate you plan on using.

Top 2 Substrates For Bettas

There are a lot of different substrates you can use, which makes it hard to pick what’s best. Listed below are some of the most common substrates, as well as the pros and cons of using them.

Aquarium Gravel

One of the most commonly used substrates, gravel is a classic. You can get aquarium gravel in any pet store or aquatic center. You can also get it in a lot of different colors, but I definitely think the more natural colors are better


Some of the pros of using aquarium gravel are:

  • It’s hard for a fish to stir up. While betta’s don’t usually do this other fish you plan on housing your betta with might. If you have a substrate that is easily stirred up, it can make the tank look messy and cloudy.
  • While food, feces, and plant debris may fall into the cracks of gravel, one of the benefits is that it’s easy to clean. You just have to take some time out with a gravel vacuum.
  • As long as you get pea size gravel, you don’t have to worry about your betta eating any of it.
  • Because gravel isn’t as compact as other types of substrates it’s a lot easier for plants to grow in.


  • On the subject of plants, if your gravel isn’t compact enough, you may notice your plants dislodging and floating around the tank.
  • Gravel can often be sharp, which isn’t good for your betta. If your betta swims to low it may scratch itself and get a wound. This will result in an increased chance of disease and illness.
  • Live food can often hide in gravel, making it harder for your fish to eat them, as well as an increased possibility of them overbreeding.

So Is Gravel Good For Fish Tanks?

Gravel is definitely a strong contender. As long as it’s smooth, pea-sized or slightly bigger and quite compact it’s an excellent choice. If you’re wondering what type of gravel to get, pea gravel is probably your best bet.

Aquarium Sand

You can also add aquarium sand to your betta tank. Aquarium Sand is normally used for bottom-dwelling fish, but that doesn’t mean you can’t use it for your betta. In fact, aquarium sand may be more like your bettas natural environment than gravel.


  • One of the biggest benefits of using sand is that it’s a lot more compact. This level of compactness means that any debris such as food only sits on the surface of the sand. If you have a bottom dweller in your tank, they’ll be able to eat this. And if you don’t have a bottom-dwelling fish, all you need to do is hover a gravel vacuum an inch above the sand.
  • And the other benefit of sand is the fact that there are no sharp edges. If you plan on using sand you don’t have to worry about your betta hurting themselves.


  • Although it doesn’t happen often, sometimes a build up of bad bacteria can occur in air pockets inside the sand. This build-up can release hydrogen sulfide into the tank which is bad for your fish. To stop this happening you have to gently swirl the sand frequently.
  • When you first put sand into your tank it may swirl around making the water look dirty. This will also happen every time the sand is disturbed.
  • Because sand is so compact, it can often be hard for your plants to dig their roots down. As well as this you may have to weigh your plants down with rocks, as it’s too light to keep some plants anchored down.

Coral Sand

Along with aquarium sand, there is also coral sand. However, whilst it’s called coral sand, don’t be fooled as it’s more like gravel. Whilst coral sand is good for a lot of fish, I wouldn’t recommend it for your betta. Coral sand is made of calcium carbonate, that slowly dissolves in water.

This process, changes the pH of the tank making it less acidic and more alkaline. This isn’t good for bettas who prefer more acidic environments.

coral sand

Can You Put Sand In A Bettas Fish Tank?

If you plan on using sand for your betta’s tank then I would definitely avoid using coral sand and stick to aquarium sand. Also, a lot of people think they can just buy play sand or use any sand. I’d avoid this too. Oftentimes some of the ingredients in the sand (especially play sand) can cause a bloom of brown algae or harbor other bacteria.

Is Gravel Or Sand Better For An Aquarium?

While there are other substrates that you’ll soon find out about, gravel and sand are the main two. So which one is going to be better for your betta? Personally, I use gravel, I feel like the benefits of gravel far outweigh the benefits of sand. And on top of this, it also looks a lot better. However, if you want to use sand then it’s also not going to cause a problem for your betta.

Other Types Of Aquarium Substrate

Now that you know about the main two substrates you should choose for your betta here are a few more.


Marbles can be used as an effective substrate for bettas. When getting aquarium marbles you normally end up getting marbles that are flat, not round. And flat marbles do look a lot more pleasing than round ones.

However, remember, that marbles may not be the best choice of substrate. There are often large gaps in between them, which make it easy for food and feces to slip in. The good news is if your betta has babies, it’s possible that these gaps can become a safe haven for the fry.

Marbles are great for tanks that are going to be cycled regularly. If you have a smaller tank then marbles are your best bet. At this size, they are much easier to keep clean over sand and gravel.

Marble Chippings

You may have heard of marble chippings for your betta tank, but this is one that should also be avoided. It’s similar to coral sand, as it’s also calcium carbonate based. However, the benefit is it’s cheaper.

Natural Stones (River Stones & Stone Aggregate)

Some people say you can use stones from a river or stone aggregate (anything natural you find outside such as stone, wood, sand etc.). This is the type of substrate that should DEFINITELY be avoided. You may think the natural look will be better, but it’s going to be dangerous to your betta. Because you don’t know what this sort of substrate is harboring. It could poison your fish, change the pH, or make your tank incredibly murky.

river aggregate

No Substrate

And the last option you may consider is no substrate. Just the glass bottom. There are a lot of disadvantages to this, but also a couple of BIG advantages.


  • If you plan on breeding your betta no substrate makes the fry easier to see. This way you can keep an eye on them and make sure none are going missing.
  • No substrate is the easiest to clean. Without having to worry about sucking gravel up or changing sand, all you have to do is quickly use a gravel vacuum.
  • There’s no chance your betta is going to hurt themselves or eat the substrate when there is none.
  • There’s also going to be an extra 0.5 – 1 inch of swimming space for your betta too!


  • Previously mentioned, sometimes a glass bottom can cause reflections in your tank, causing your betta to flare up. If this happens too often your betta will become extremely stressed.
  • Bettas love plants, and if you don’t have any substrate you’ll have nothing to anchor plants in.
  • It’s going to be harder for beneficial bacteria to grow. Which can cause an increased buildup in dangerous chemicals (such as ammonia).
  • It just doesn’t look as nice. Not many people like a bare tank,  because it’s not nearly as appealing for you or your betta.


This aquarium substrate guide should have answered all your questions regarding which substrate you should use. And here’s a recap of some of the main points.

  • The two best substrates you can use for your tank are gravel and sand.
  • Gravel is good because it anchors plants easier and produces more beneficial bacteria.
  • Sand is good because it is easier to keep clean and is less likely to hurt your betta
  • You can also try using marble or no substrate
  • You should avoid coral sand and marble chippings and definitely avoid any substrate you’ve found in the wild.
  • Aquarium substrate will make your betta feel more at home as well as making the tank look more natural.

If you liked this article, make sure you check out the rest of the website! And if you have any more questions you can ask them in the Q&A Section!

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