Live rocks are more than just beautiful additions to enhance the overall look of the aquarium, they are natural water filters as well. They come in various textures, sizes, colors, and structures which enhances the aquarium and serves its purpose of being aesthetic, well. 

So, can you use live rock in a freshwater aquarium? The answer is No. Introducing a live rock in a freshwater aquarium will destroy all the living organisms which will then contaminate the water. This is the complete opposite of what this type of rock should be doing. 

The most common and safe rocks for freshwater aquariums are slate, granite, and quartz. 

For Aquariums, What is Live Rock?

Live rocks are fragmented pieces of coral reefs that are old or have broken during a storm or have been hit by strong waves. Their name may indicate that they are alive, but they are not living creatures even though a lot of reef creatures make it their home. 

The ones picked up right away from the ocean, have coralline algae all over them. If not the time periods they’ve spent in the ocean is the home to various reef creatures and also turning into different shapes so that these creatures can find refuge differentiates them from “normal rocks”. 

While there are some rocks picked up from the ocean there are also rocks that are born in the ocean itself. How? From the remains of coral skeletons. 

What are Dry Rocks?

Dry rocks are also known as base rocks. These are live rocks, but they have no life growing on them or inside them. If you do not manage to take good care of the live rock ecosystem this is what happens. 

What are dry rocks used for? For decorations only. Sometimes, they are preferred over live rocks since they are much cheaper. 

Dry rocks cannot have organisms growing on them. Dry rocks are calcium-based which will harden your water and if you cannot raise the hardness in your tank any higher then you shouldn’t use dry rocks. If you can have hard water in your tank then you can surely use dry rocks. 

We recommend you not opt for dry rocks since they are not much different from live rocks. Dry rocks and live rocks are not the best options for freshwater aquariums. You have a long list of different rocks for freshwater tanks that are safe, opt for those instead.

Are Live Rocks More Suitable For Saltwater Tanks?

Freshwater tanks do not have a specific craving for live rocks. Basically, there is no urgent need for live rocks in freshwater tanks. For freshwater aquariums, live rocks are usually nothing more than just decorations. 

Since live rocks are brought from the ocean itself they are more suitable for saltwater aquariums. Like saltwater, freshwater cannot manage to keep all the living organisms alive that live on the rock. The organisms can survive only in saltwater. 

Even though using a dry rock or dead live rock may not be the absolute safe option for the environment of your aquarium, you can still use it. We suggest you do not take the risk and go along with the safest option of using them in saltwater tanks only. 

There are many hobbyists that convert their freshwater aquariums into saltwater aquariums after they notice that the environment of their freshwater tanks has vanished away! 

You should mix freshwater along with salt. If you do not do so, all the living organisms that survive on your live rocks will lose their lives. 

How Do You Choose the Right Aquarium Rocks?

Since everything you choose to put inside your tank contributes to making the environment for your animals better, it should be chosen wisely. Even simple decorations like these rocks should be chosen carefully. 

We recommend you to search about the type of fish you have as well as the water condition you want to keep in your tank and then proceed to buy a particular type of rock. 

After you purchase the rocks from the store it is always necessary to wash each and every rock you’ve purchased from debris or any sort of bacteria on them. You never know what components must have been present on the surface these rocks you purchased sat on. 

On the other hand, there are certain rocks that should be avoided. When it comes to freshwater tanks, unfortunately, live rocks for all the reasons already given should be avoided. 

Sharp rocks or even rocks that are weak and can break apart quickly have to be avoided at all costs! Their sharp edges can easily harm your fish and hence they are unsafe. 

If you happen to pick up a rock yourself and cannot identify its type, leave it right there because you cannot use it in your tank. Unless and until you can identify the type of rock you have picked up as well as its components only then you can call it unharmful for your fish. 

Safe Freshwater Live Rocks

Freshwater tanks cannot deal with live rocks at all. Live rocks will kill all the living organisms who are surviving on or in the rock and that will lead to the contamination of the water with bacteria and algae. 

You may think buying dry rocks is a safe option but no, that’s not true. Dry rocks are not going to be a healthy choice for your fishes again. Aragonite, which is a form of calcium carbonate, is what the coralline skeletons are made of. This can make your water very hard and will also make it really difficult for your fish and other living organisms to survive in the tank. 

Now, you can always buy particulate filters as well as clean the tank regularly and get rid of these components easily. But when you have attractive rocks that would fit your freshwater aquarium perfectly, why would you want to waste your time and energy on those filters? 

There’s a good variety of choices for you to choose from when it comes to rocks for your freshwater aquarium. The presence of these rocks won’t provoke you to look for anything else. While if you decide to use rocks like dry rocks or live rocks in freshwater tanks, you will be risking the lives of your fish and other living organisms living in your tank. The good choices of rocks for freshwater tanks are as follows: 

You can choose the right type of rock for your aquarium keeping the aquarium environment in mind and the other factors mentioned in how to choose the right aquarium rocks for your tanks. 


It’s not really a rule to not use live rocks in a freshwater tank, it’s just that they aren’t the best options available out there. 

Think about it this way, would you want to ruin your aquarium environment only for decoration purposes? No, right? We guessed as much! 

You would have to risk the lives of your fishes as well as spoil the ecosystem of the live rock together. 

Why do all of that when you can just simply choose the perfect rock that suits your tank environment the best?

Also, remember that dry rocks are not much different from live rocks when it comes to storing them in freshwater tanks. Dry rocks will stay as dry rocks in freshwater tanks since no living organisms can grow in or on them. 

Well, you can always make your own live rocks.