How often should you change gravel in a fish tank?

Last Updated on January 18, 2021 by cmoarz

If you own an aquarium, you probably have gravel stone installed in the tank. The gravel is an integral part of the aquarium, and it benefits the fish as well as makes your aquarium look good. And with a wide selection of colors available, it becomes an ideal piece of decorating material.

But the question of how many times you should change gravel in the fish tank is subjective because there is no strict rule to follow. And more importantly, you don’t need to keep changing the gravel unless you want some other color coating to decorate the tank’s aesthetics.

Gravel stones are not corroded easily and can last for very long periods. But what you need to do is keep them clean by washing them frequently. Suppose you don’t wash for more extended periods. In that case, there is a tendency to accumulate excess bacteria and the growth of other microorganisms, which are potentially harmful to the fish. And if the gravel is not well maintained, it also makes the aquarium look bad and dirty. Over time, even the color coating tends to disappear because of the excess growth of microorganisms.

So the ideal question is, how often should you change then aquarium water and clean the gravel. And there are no strict rules to follow but typically, once a week or once in two weeks is an ideal start. But it would help if you also remembered that it depends on your aquarium’s size and how many fish you have. If the aquarium is small and you have many fishes, you would need to clean it at least twice a week because it will get dirty quickly.

How long does aquarium gravel last?

Aquarium gravel is natural stone fragments that come in different sizes. Typically, the ones used in aquariums are anywhere below 3 mm in diameter. And they can last forever. So you don’t have to worry about frequently buying gravel stones and changing them.

But the only reason some people keep buying and replacing the gravel stone is for decorating purposes. For example, if you have an aquarium with brightly colored fish and black color gravel, but you decide to purchase a darker color or black colored fish, then you will need to replace the gravel. Otherwise, people will not notice the fish, and the tank will look unpleasant because there is no contrast with the fish’s color. So you will need some light-colored gravel like white or pink to bring out the fish’s color contrast.

So it is all a matter of personal choice. And if you are an avid aquarist who likes adding new fish and keeping more than one aquarium, replacing the gravel stone becomes necessary. Because each time you add a new fish, it will tell you whether you need to change the gravel. And you can also mix the gravel with different colors to make it more interesting.

And there is another thing you can. You can purchase the colors you like and keep them with you. And when you feel like changing the gravel to suit the fish’s color, you can remove them gently when you wash the tank and then replace them with a new one.

Three signs you need to change the aquarium gravel

Changing the aquarium gravel is not a necessity but changing the water in the tank is. Typically, once you put the gravel in the tank, you don’t have to change it. But here are three signs that can signal you to change the aquarium gravel.

  1. Wrong color choice

The most common signal for changing your aquarium gravel is using the wrong color gravel. Gravel stones come in different colors like pink, blue, yellow, orange, black, etc. When you buy some new fish and put them on the tank, sometimes the colors look similar to the gravel. For example, if you have orange color gravel and you get some red or orange color fish, the fish does not become visible as it should be. So, in this case, you should change the gravel by choosing the appropriate color.

Therefore, you should keep in mind that having similar color gravel and fish is not an ideal combination. Always look out for the best color combination that can make the fish visible to others.

  • Gravel stone leaching

Most of the commercial gravel stones come coated with a layer of paint that gives them their color. Generally, they do not leach into the water or corrode easily. However, if you have used the gravel for a very long time, the sign of wearing out is a possibility. And the paint leaches into the water, and it can cause chemical reactions that can affect the fish. You will notice the coating chipped off in small parts, which happens after frequent cleaning and rinsing.

Gravel stone coating is durable, but the possibility of leaching is also there. Therefore, keep an eye on the layer every time you change the tank water and rinse the gravel stone. If you notice the coating wearing off, the best advice is to change them with a new gravel pack.  

  •  The health of the fish

Although this does not often happen, some fish are more vulnerable to health problems, and gravel stone does not supply nutrients to keep the fish healthy. If you notice that the fish’s health is deteriorating despite proper diet and clean water, removing the gravel and substituting it with a substrate is the best option. Substrates can supply useful nutrients to the fish. So you can change the gravel and see if there is an improvement in the fish’s health.


Aquarium maintenance is crucial if you want to keep your fish alive. And having a bottom filled with gravel stones is ideal because it creates a sound environment. And since most of the gravel stones available in the market come meticulously designed to keep your aquarium beautiful and safe, changing the gravel does not often arise.


Owner of and also owner of actual Aquarium Gravel believe it or not! ;). Setting up beautiful aquarium sceneries and habitats since I was very young. Enjoy!