Aquarium Gravel

Aquarium gravel, or most commonly known as the substrate, is usually found in many pet shops. This aquarium accessory helps make the tank more attractive, especially in various colors and sizes, from tiny pebbles to large river rocks.

On the flip side, it serves a great purpose beyond just decoration though there are some situations in which a substrate might not be for every aquarium.

Do aquariums need gravel? Yes, gravel is important to many aquariums because it promotes a healthy environment for fish to survive. Keeping this in mind, while it might not be necessary, it should always be your priority.

In this article, you will find out more information regarding gravel and the answer if it is really necessary to be in your fish tanks or not.

To help you decide, I have listed some of its benefits that you and your fish will be happy about.

What Is A Substrate?

You might not realize it, but it is possible that you already encountered a substrate on one of your visits to a local pet shop.

When you visit your local pet shop and go to some aquariums available, the substrate is actually any loose materials that make up the bottom of any tank. If you see some pebbles at the bottom of the aquarium, those are actually substrate.

Although it doesn’t have to be pebbles, it can be anything.

Gravel is another example of a substrate, and it is not actually a necessity. Your new fish tank will still survive and work properly without it. But compared to everything in this life, not every essential thing is a necessity.

This principle can be said for substrates like the gravel. To fully understand its concept, you need to pay attention to what goes on inside your fish tank.

The fish you keep in your tank eat food, digest it, and eventually produce waste. This process goes on and on until the quality of waste in your fish tank reaches its limit. As a result, this can be pretty harmful to your fish.

The Benefits Of Having Gravel

Gravel will be responsible for taking care of the ecosystem in your fish tank. There are many benefits it can give to your aquarium. Here are some of the few benefits you can get from having gravel:

Biological Filtration

The most obvious reason why you need gravel is that it provides a home for beneficial bacteria.

These bacteria colonies will be the one responsible for eliminating waste of fish, leftover food, and some debris of the plant.

The bacteria can live without a comfy gravel bed, but they might not be able to grow in many quantities to keep your aquarium safe for your fish.

If you opt not to have gravel in the bottom of your fish tank, it will be necessary to change your water more often to keep harmful waste from building up.

If you have a heavily stocked tank, even frequent water changes won’t be enough to keep ammonia and nitrites at bay. This is why it is critical to have a substrate to maintain a healthy environment for your fish.

Fish Habitat

Having gravel is part of creating a pleasant environment for your fish. It gives the fish, especially the ones who like to burrow, a place to hide.

It also provides them enrichment for bottom-dwellers that prefer to forage through the gravel for bits of food. This also helps to reduce reflections within your aquarium tank that can eventually stress your fish.

Gravel can also be used to improve the overall chemistry of the water.

For example, if your fish require hard water, a coral substrate can help you achieve the water’s proper balance.

It helps mostly in the overall fish habitat as it can provide a safe home for fish to lay their eggs. Having larger substrates allow eggs to drop out of reach of hungry fish.

Home For Live Plants

Not only a substrate is good for your fish, but it can also be helpful to your live plants as it is critical and second only to lighting in keeping your plants alive.

With enough substrate, it can ensure that your plants root well and have their nutritional needs met.

Aside from gravel, laterite and vermiculite are common substrates for planted tanks as they can store and release nutrients for the plants.

They are a perfect combination with gravel so make sure to get a combination of both. Some aquarium plants with more substantial roots require extra depth to the substrate, so you need to consider when assembling your tank.

Why Choose Gravel?

In terms of choosing the right substrate, gravel makes sense in a lot of scenarios. If you opt for gravel as a substrate, it can increase water flow in your tank.

This increased water flow reduces the build-up of harmful microorganisms that can diminish the fish tank’s overall health.

In addition to that, the weight of gravel makes it less likely to get sucked in your aquarium filter if you have one installed.

Gravel also has its visual appeal. There are darker shades that work perfectly as a background against which your fish can actually stand out.

This is probably why gravel is one of the most common and popular choices when it comes to substrate types.


In conclusion, if you look into animals’ science and behavior, they live best when you see them in a proper environment that resembles their natural habitat.

This can also be applied to fishes, and when choosing a substrate, you need to make sure to choose the one that mimics their natural habitat back in the ocean.

Try to at least copy its function and form, from the substrate’s nature to its form. Always remember that the substrate should also complement the rest of your aquarium and not work against it.

It will allow you to save money and time in the long run because you made the right choice in choosing the gravel as your substrate option.