How Much Gravel Does My Fish Tank Need

The gravel in your tank is very important. It is, in fact, more important than you (probably) think. In case for some reason you don’t know what gravel is, it is the substrate that sits at the base of a fish tank. It is one of the several types of substrates that can be used at the bottom of a fish tank.

Setting up an aquarium from scratch is not an easy thing to do. There are several things to think about and to decide during the process. One of the things you need to decide is how much gravel your fish tank needs. 

In this post, I will share with you everything you need to know to decide how much gravel is perfect for your tank. 

What to Consider When Deciding the Amount of Gravel to Add To Your Fish Tank

Below are four important things to consider when deciding the amount of gravel you need to add to your fish tank.

1. Plants

If you are going to add live plants to your aquarium, you need to add a good amount of gravel to your tank. If you are not going to add live plants to your aquarium, you can probably get away with adding a small amount of gravel to your tank.

Plants that have root systems require a suitable type and amount of gravel, while plants that do not have root systems can do with just about any plant-suitable type of gravel. The best gravel for plants that have root systems is fine gravel and it should be deep, while the best gravel for plants without root systems or with smaller systems is coarse shallow gravel.

2. Fish Species

You should consider the fish species you are going to have in your tank when deciding the type and amount of gravel to add to your tank. This is because different species like different types and amounts of gravel. 

For instance, some fish species like loose and coarse gravel that they can play around in while others prefer fine and deep gravel that they can dig and forage in. 

So think about the fish species you are going to introduce as this will help you to find out the type and amount of gravel you need to add to your tank.

3. The Size of Your Tank

The size of your tank is one of the most important things you need to consider when deciding the amount of gravel to add to your tank. The bigger your tank, the more the gravel you are going to need to add to your tank. And the smaller your tank is, the smaller the amount of gravel you are going to need to add.

If you have a small tank, try to make sure the layer of gravel in your tank does not exceed 2.5 inches from the base of the tank. This is because 2.5 inches is often the level that looks good in small tanks. 

4. Decorations

If you are going to add decorations to your tank, you are going to need a significant amount of gravel at the bottom of your tank. This is because a significant amount of gravel is what you need to make your decorations look great at the top. 

As you can see, there are several things you need to take into account when deciding the type and amount of gravel to add to your tank.

How Much Gravel Your Fish Tank Needs

There are no hard and fast rules when deciding how much gravel to add to your fish tank. 

However, experienced aquarium hobbyists recommend adding 1.5 pounds of gravel per gallon of water when setting up a fish tank. Adding this amount of gravel per gallon of water in a fish tank usually yields a deep and aesthetically pleasing level of gravel. 

By taking this recommendation and the four considerations above into account, you should be able to easily decide the type and amount of gravel to add to your tank.

Going by the recommendation from experienced aquarium hobbyists, below are the recommended gravel amounts for popular beginner tank sizes. 

 

Tank Size  Calculation  Recommended Gravel Amount 
400;”>5-gallon tank 1.5 lbs. per gallon *  5 gallons 7.5 lbs. 
10-gallon tank 1.5 lbs. per gallon *  10 gallons 15 lbs.
20-gallon tank 1.5 lbs. per gallon *  20 gallons 30 lbs.
55-gallon tank 1.5 lbs. per gallon *  55 gallons 82.5 lbs.

 

While the recommendations above are made by experienced aquarists, do not take them as gospel truth. This is because tanks are different. Some tanks are tall while others are short despite having the same volume. So while a certain amount of gravel may look deep and aesthetically pleasing in one tank, the amount may be impractical to have in another tank of the same volume. Therefore, use the recommendations above, the four considerations discussed earlier, and your own discretion to determine how much gravel your fish tank needs. 

Aquarium Gravel FAQs (Frequently Asked Questions)

How Thick Should The Gravel In My Tank Be?

If you are going to plant your aquarium, you should make sure the gravel in your tank is approximately 2.5 inches thick. This thickness of gravel is great for plants because it allows plants to establish their roots nicely and thrive. 

If you are not going to plant your aquarium, the amount of gravel you are going to add is not really important. However, you should make sure the thickness is approximately 1.5 inches for aesthetic purposes. 

How Thick Should The Gravel in My Tank Be If I Want To Plant Sword Plants?

Sword plants are popular aquarium plants. However, they are deep-rooted plants. In other words, they have root systems that go deep. Therefore, they need deep or thick gravel. How thick? Experienced aquarists recommend at least 4 inches. 

So the answer to this question is 4 inches. 

How Thick Should The Gravel in my Tank Be If I Plan To Install an Undergravel Filter?

If you plan to install an undergravel filter, you should make sure your gravel is at least 2 inches thick. This minimum thickness will allow your undergravel filter to work properly. If your gravel is less than 2 inches thick, your undergravel filter will not work right because gravel is the thing that acts as filter media in undergravel filters. 

What Should I Use As Gravel Instead of Gravel in My Tank?

If for some reason you do not want to use gravel in your fish tank, you can use smooth pebbles, aquarium rocks, and commercial substrates. You can also use sand which is actually the ‘gravel’ recommended for marine tanks. Some newbie aquarists do not add any kind of gravel. This is not recommended.

What Should I Add First – Water or Gravel?

You should add gravel to your tank first and everything else except your fish before adding water. This is the best way to set up your aquarium. However, if for some reason you add water first, you can still add gravel after. This will make a mess especially if the gravel is fine but it everything will settle within 30 minutes. 

How Often Should I Change My Gravel?

There is no need to change the gravel in your tank. In fact, it is not recommended because beneficial bacteria usually make the gravel their home within a couple of weeks. When your gravel gets dirty, the best way to take care of the dirt is to vacuum it. 

Conclusion

As you can see from the information above, there are several things to consider when deciding how much gravel to add to your tank. It is my hope that this article has made it easy for you to decide how much gravel your fish tank needs.