Gravel is the best option for betta tanks if you want to avoid maintenance. Sand is the next best option, but it can be compacted and needs to be raked for the aquarium to be healthy. Marble is not a good option, since it traps a lot of betta debris and you have to move it to clean it properly. Gravel is, in general, the most common aquarium substrate and an excellent choice for a Betta tank.
From aquarium sand to pebbles and natural gravel, choosing the right substrate for your betta fish tank can be a challenge. Seachem Flourite is an excellent choice due to its porous nature and lack of harmful chemical treatments. This gravel works well for root-feeding plants or fish tanks with a variety of mixed substrates. Spectrastone Shallow Creek Regular Gravel Substrate is a great value and comes with plenty of gravel to keep your betta fish happy for years to come.
Spectrastone Shallow Creek Regular Aquarium Gravel creates a natural and discreet look for your betta tank. The included fine gravel comes in a variety of colors, from brown to yellow, allowing the anchor plants in betta aquariums to have a safe place to settle and grow while maintaining their natural appearance. Be sure to carefully clean the gravel before placing it in your tank as what looks like almost fine gravel can be dust that has settled inside the bag over time and that must be cleaned so that it does not affect the water in the tank. Betta fish prefer a relatively neutral to acidic pH range of 6.5-8.0, which means that this substrate works perfectly for them.
Be sure to measure the pH before and after adding more gravel, as a larger amount can affect the overall range of your tank. If you're looking for a more basic tank, this substrate may not lend itself well to that. Volcanic gravel tends to be acidic, so it works well for betta fish, but it may not be the best for fish such as African cichlids. The smooth, rounded edges of BLQH Gravel River rocks are sure to please your betta fish and even burrowing fish such as plecos and catfish won't have to worry about sensitive areas such as gills or chins being damaged.
Pure Water Pebbles Ocean Aquarium Gravel has bright blue coloring that can really make the colors of your betta fish stand out in exciting ways. The acrylic coating on the gravel pieces also means that the colors will last for many years without causing any change in the chemistry of the water. Caribbean sand is a great natural sand substrate that can work alone or together with other substrate options for betta tanks such as pebbles, rocks or gravel. Neutral and non-toxic, this sand can recreate the natural habitat of rice fields and tropical waters in your home.
Unfortunately, with some filtration systems such as HOB filters, fine sand particles can get trapped in the mechanisms and disrupt their operation. Make sure to let the sand settle before turning everything on for the first time and quite a bit of sand may be needed to cover a large surface, releasing gases that can discolor the sand for a short period of time. In their natural habitat in shallow waters of Southeast Asia in Thailand and Korea, bettas really can't choose between natural and artificial substrates as they are very adaptable fish living in areas of sand, dirt and gravel. Gravel and sand provide beneficial bacteria with a place to spread and multiply, meaning that this biological filter can naturally reduce ammonia levels in the tank.
The best substrate for betta fish is gravel or a combination of gravel and sand as they provide enough space for beneficial bacteria to thrive and keep ammonia levels in the tank low. However, some gravel can be quite rough and can damage fish when it touches them, especially if your aggressive betta decides to carry its own reflection and falls on rough gravel which can be especially harmful to sensitive areas such as gills and eyes. The use of certain substrates such as sand can be quite expensive as a primary substrate because many tiny particles are needed to add real depth to the base of the tank unlike larger options such as gravel and pebbles or marble substrate. As mentioned above, the overall choice is up to you but my recommendations are gravel, sand or a combination of both depending on your needs.
