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Many people think sand and gravel are no different, but that’s not true, especially for freshwater tank use. If you’re undecided on which one to go with, here’s a rundown of the pros and cons of both options, and a few tips on making the right choice.

My Favorite Substrate Isn’t Gravel Or Sand

Sand as Freshwater Tank Substrate – The Advantages

Sand is very popular among freshwater aquarium owners. It’s aesthetic and lends a very natural vibe to the tank. And obviously, you can get it from any aquarium or pet shop, besides being cheap.

Certain types of aquarium sand fit perfectly with burrowing fish or creatures (for example, snails and crabs), while others are great for nutrient-absorbing rooted plants. All of them, though, are remarkably easy to use.

Another good thing about sand for your freshwater tank is that waste matter, such as fish poop and leftover food, only stay on top of the surface instead of settling at the bottom. That’s the main reason we’ve said this substrate is highly convenient.

How Sand May Not Be Best for Your Freshwater Tank

While there are several benefits to using sand, it will not be the right choice in some cases. After all, not all sand is the same. Some types are too dense to promote root growth, while others can hardly meet the general nutritive requirements of plants.

Plus, sand tends to be quite messy when your fish starts stirring it around. When that happens, it will take time before it settles back at the bottom. And though it allows tank waste to remain on its surface, it can cause other issues like clogged tubes and filters.

What you might like the least about aquarium sand is its tendency to create gas pockets known as anoxic zones, or anaerobic dead zones, which are potentially dangerous for both your pets and the plants. Interestingly, anoxic zones can be prevented by stirring the sand from time to time, but you may not want to do that again.

Gravel as Freshwater Tank Substrate – The Advantages

You can order aquarium gravel in plenty of shapes and sizes, and even different colors. That means it can make your tank look attractive, although it still depends on the environment you want to build for your fish.

When it comes to size, you’ll want to go with pea-sized, which makes cleaning easier. Just scoop them out and wash them in running water, and they’re good as new. It’s also the healthier choice for your fish and plants. Just make sure you choose smooth gravel, so your fish don’t get cuts or scrapes.

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As to your plants, they will love those tiny spaces in between the rocks. Even the rocks themselves are suitable for growing bigger root networks, and faster at that.

Another thing you may not know about aquarium gravel is its inertness. That means it’s not going to affect your tank’s water chemistry in any way, making it safe. And, of course, gravel is big and bulky enough not to float around and make a mess or clog things up, like your filters and all.

How Gravel May Not Be Best for Your Freshwater Tank

Gravel is generally easier to clean, but food bits and other waste can insert themselves in between the rocks, and sometimes, you would need a special vacuum to get them out. That gets hard in some cases and even causes a significant decrease in water quality.

Additionally, fish can pick at the gravel, hurting their teeth (if any) and causing buoyancy problems. Worse, they could die when they choke on the rocks or ingest them. Gravel is also known to harbor bacteria, so when a fish cuts or scrapes itself, it could lead to infection.

Sand vs. Gravel: Choosing by Comparing

Sand and gravel each have their pros and cons that make choosing a chore. Before you decide which one to have for your aquarium, make sure you have weighed the advantages and disadvantages, focusing on the following crucial points:

Your Fish and Plants

If your pets like to dig in the substrate, go with sand as gravel can harm them seriously. If your tank has lots of plants, gravel will be better to sustain their nutrition and root systems.

Maintenance Equipment

This part can put you in a dilemma. Sand is excellent because waste sits on top of it, making cleaning easy. But remember that sand can cause a mess when stirred around and can even end up in your filters. On the other hand, gravel is so much easier to clean as you can wash it, which is plain impossible with sand.


Either sand or gravel is fine as long as it’s inert, but make it a point that they don’t cause a sudden increase in the water’s pH, nitrate or ammonia level.


Take note that sand will have to be replaced regularly, which can be cumbersome. In contrast, you can only buy gravel once as long as you keep it clean by washing.

Wrapping Up

And that’s about everything you need to know about sand and gravel for your freshwater fish tank. Try to make the most well-informed choice possible. Consider your lifestyle, whether there are kids in your home, and other little things that can impact your decision.

For example, if there are kids in the house, you know they’re likely going to dip their hand into the water, so sand is definitely out of the question. If you don’t like the idea of replacing your substrate regularly, choose gravel.

Pick not only what’s right for you, but more importantly, what’s suitable for your pets and the environment you will be giving them by adding sand or gravel as your substrate.

Comparing Gravel To Sand For Freshwater Tanks