How Much Gravel Do You Need for Your Aquarium?

How Much Gravel Do You Need for Your Aquarium?

If you’re planning to set up an aquarium, you’re probably thinking about the types of fish. However, there are other aspects to consider such as how big it should be, what food you need to get, etc. But, the one thing that most people fail to consider is how much gravel should be put into an aquarium.

If you haven’t given this matter any thought, you aren’t the only one. Many people have trouble deciding what kind and how much to get. Gravel is essential for the aquarium, and it helps maintain a healthy and clean environment, apart from providing aesthetic value.

Let’s have a look at what gravel is and how much you would need for your aquarium.

What is Gravel, and Why is it Used?

Gravel is a type of substrate, which refers to the layer at the bottom of the aquarium. It can also consist of aquarium soil or rocks, but most people stick to gravel. It consists of small fragments of stones that are broken down to make a porous substance. It has a high weight and density, which is why it settles at the bottom of your aquarium.

Gravel can be found in varying levels of coarseness, ranging from very fine to coarse, and you can choose whichever one you want. It is safe to use as it doesn’t contaminate the water.

Since it has porous qualities, gravel can help trap any impurities or dirt present in the water. However, it can also trap fish food or waste underneath, thus making the cleaning process much more difficult.

Another reason why gravel is essential for your aquarium is because tanks usually have reflective bottoms, which can cause the fish to get disoriented if there is no substrate layer. The gravel also facilitates the production of healthy bacteria in the aquarium, making it a better environment for fish.

The gravel layer inside your aquarium shouldn’t be more than 3 inches, and you can choose the quantity according to a few factors, such as the type and number of fish, ease of cleaning, etc.

How to Choose The Right Gravel

You should consider certain factors while choosing the right type and quantity of gravel for your aquarium. Some of the crucial elements are:

Type of Fish

The type of fish you keep will have an impact on how much gravel you should put inside it, as well as how coarse it should be. Coarse gravel is more suitable for certain types of fish, while other fish prefer to swim around with fine gravel as the bottom layer. Once you have decided what kind of fish you are keeping, you can figure out what type of gravel you need.

Aquarium Plants

The type of aquarium plants you put in also impacts the type and quantity of gravel you choose. If your plants are without a root system, then any kind of gravel will work fine. However, rooted plants require specific types of gravel to thrive. If you choose big rooted plants, you will have to choose very fine gravel.

Aquarium Size

Last but not least, the size of your aquarium is also essential when you are choosing the type of gravel. The size refers to the tank’s dimensions and its water capacity, which is usually in gallons. So, naturally, the bigger the aquarium, the more gravel you will require.

If you place decorative accessories inside your aquarium, it will also change the type and coarseness of gravel that you should have. The more decoration you have, the finer the gravel should be.

Moreover, if you have heavier accessories, you will need more gravel to make them settle at the bottom.

How Much Gravel Do You Need for Your Aquarium

How Much Gravel Do You Need for Your Aquarium?

Now comes the most crucial question: How much gravel do you need in your fish aquarium? As mentioned above, you only need up to 3 inches of gravel, but you can start with a 2-inch layer too.

The dimensions of your aquarium help determine the correct quantity of gravel. For example, for an approximate calculation for a 2-inch gravel bed, multiply the length of the tank by its width. Now, divide this figure by 10, and you will have a rough value of how much gravel you need in pounds.

Another general estimate is that you should have 1 pound of gravel per gallon of water. So, if you have a 50-gallon aquarium, you will need roughly 50 pounds of gravel for it.

Don’t go overboard with your calculations, as it can harm the aquarium and the fish you put in it. The more gravel you put inside, the less water it will hold, and this also reduces the oxygen concentration.

How Often Should You Change The Gravel?

Simply adding gravel to your aquarium isn’t enough. It also requires regular maintenance, and you have to replace it after some time. If you have high-quality gravel, you can clean it using a vacuum or blower to remove the dirt particles.

Make sure to buy gravel from a trusted source that doesn’t compromise on quality to make it last longer.

Moreover, make sure to layer the bottom of your aquarium with gravel before adding any water or decorations. This way, it will settle properly. Also, ensure that the food particles in the water don’t sink to the bottom of the gravel layer, as they rot faster and create a harmful environment for fish.


So, as you can see, gravel plays a vital role in maintaining a clean and healthy environment for fish. The quantity and quality of gravel you choose depend on several factors, including the type of fish and the dimensions of your aquarium.

Hopefully, this guide has helped you select the right type and quantity of gravel for your aquarium. This way, your fish will have a comfortable environment to thrive in for years.