Is It Safe to Put Sandstone in an Aquarium? We’ve Got the Correct Answer

If you want more appeal and fun to your aquarium, you may have thought about adding aquarium accessories. The simplest way is to use sandstone options.

Are you struggling with questions, “Is it safe to put sandstone in an aquarium?” or “which stones should I use for my fish tank?”, this article will guide you.

Let’s get into the details to see more!

Sandstone in Aquarium

Sandstone is safe to put in an aquarium

Sandstone is safe to put in your aquarium, provided you choose the right one. Yet, the consequences could be dire if you choose unacceptable sandstone.

You can also use sandstone rocks incorporating gabbro, dolerite, and basalt. Just ensure the sandstone you add is not dangerous.

Some sandstones are full of chemicals that can kill your aquatic inhabitants over time. You need to be careful when choosing the Sandstone for your aquarium. 

What Kinds of Rocks Are Safe for Aquariums?

  • Metamorphic Rocks: They emerge from the change of existing stone sorts. When the original stone is exposed to strain or hotness, it will lead to a synthetic or physical change.
  • Sedimentary Rocks: These rocks are formed by the testifying or collection of minor particles and resulting cementation.
  • Igneous Rocks: They are lustrous or translucent stones.

Stones have always been famous decorations for freshwater aquariums. It will be great to mix them up with tiny smooth pebbles. 

Decorating a fish tank is an individual decision. Some fish keepers prefer it to be beautiful and strong, while others love the distinctive, quelled look.

More modest tanks should go with more modest rocks. If you own a significant fish tank, we recommend searching for substantial shakes or building rockwork.

Things You Should Keep In Mind 

Always stay away from rocks with tiny pores and sharp edges. Fake rocks would be a more reasonable choice if you are on a tight budget or have minimal time to set up the tank.

Avoid over-burdening your aquarium with too many rocks, as this might break the aquarium stand or glass when adding water.

Wash any rock or sandstone before adding them to the fish tank. Allow them to absorb bubbling water for about ten minutes to eliminate all the undesirable parasites or microbes they might contain.

Secure your stones in the substrate of your tank to prevent them from falling over. Before and after you have added water, ensure that every one of you is not loosened up or moved.

How to Wash Sandstone?

A guide on washing sandstone

Step 1: You’ll need to start by collecting the necessary things. These include a broom, a watering can, and liquid pool chlorine (you can find them at any hardware & service station).

Step 2: Hose off any loose dirt and leaves.

Step 3: Mix water and liquid pool chlorine at a ratio of 5:1 in your watering can

Step 4: Pour the mix over your sandstone and leave it for about ten minutes. Ensure this mix does not dry on your stone. You should mist some water or add more cleaner to your stone if it starts to dry.

Step 5: Use the broom to agitate the wet surface of your stone and then hose off it with clean water.


  • This process will typically remove most molds, stains, and algae. If you have old or stubborn stains, feel free to repeat all the steps above.
  • Avoid using acid on natural stone. 
  • Never use a pressure washer on sandstone, as high-pressure water blasters might permanently damage the stone’s surface.


What Rocks Are Not Safe for Aquariums?

The rocks you should avoid are highly calcareous, meaning they have a large amount of calcium. In addition, avoid sharp-edged rocks that will harm your fish.

Rocks to avoid include:

  • Marble.
  • Geodes.
  • Dolomite.
  • Limestone.
  • Crushed coral or shells.

Safer rocks for aquariums include:

  • Slate.
  • Quartz.
  • Granite.
  • Lava rock.
  • Sandstone.
  • Onyx and ground glass.

Many rocks and gravels have a mixture of minerals, even in the same stone. Even if you think you’ve correctly used one stone as a safe mineral, you should always check to be sure.

What Are the Benefits of Sandstone Rocks?

  • Non-harmful and protected.
  • It is available in aquarium rock size.
  • No sharp edges.
  • Sandstone can be used for many other things.
  • It cannot change the aquarium conditions.

What Are the Different Colors of Sandstone Rocks?

Like uncemented sand, sandstone can be any shade due to debasements inside the minerals. The most popular shadings are brown, yellow, tan, pink, pink, etc. 

Can I Use Rocks Found in Nature?

Avoid adding rocks found in nature to your aquarium

You should not add rocks found in nature to your aquarium for two reasons.

First, it is impossible to know what type of pathogens or microorganisms these rocks could contain, as they are not treated with chemicals yet.

On the other hand, they may feature pH-changing qualities, which might prove fatal to your aquatic inhabitants.

As a result, we recommend only using the rocks and sandstones that are carefully chosen for various aquarium types.

Does Sandstone Affect PH?

Limestone, sandstone, senryu stone, shale, and other sedimentary and metamorphic rocks can be the best options for raising the pH as they contain large amounts of calcium carbonate.

Can I Put Lego in My Aquarium?

The short answer is Yes. Most LEGO is made from ABS plastic, which won’t break down due to natural processes.

In an aquarium, it will not leach chemicals. ABS will last a very long time and stay durable, even in the water!

The Bottom Line 

Adding stones or rocks to your aquarium is a viral trend, but it is wise to do a little research before collecting or purchasing random rocks.

Ensure your chosen stones are aquarium and fish-friendly. If you have trouble identifying good Sandstone, we recommend asking your local aquarist for advice.

Plus, always clean all stones before putting them in your tank to make it look breathtaking. Thank you for reading!