Can You Put Polished Stones in an Aquarium?

Can you put polished stones in an aquarium?Aquariums are popular ways to house lots of different kinds of pets. Although most people associate an aquarium with fish, you can use a glass tank to create a home for a great number of reptiles, amphibians and even some mammals.

And just like your own home, you want your pets living area to have a pleasant look and feel. Aquarium gravel, river rock or natural stone bought a pet store can do the trick, but doesn’t always provide the splash of color - or natural look - that most people like. So can you put polished stones in an aquarium? In most cases, the answer is a resounding “yes.”

The key to finding the best polished stones in an aquarium is to know the source of your stones - as well as understanding the needs for the critter who will live with those stones.

Just about every tumbled gemstone receives a polish at the end of its tumbled cycle. That’s how each rock stays shiny and clean. Different tumble manufacturers use different types of polish to complete this process. Some are harmless in an aquarium and others can kill your pet.

You want to avoid any sort of lacquer on the stones you use. This heavy chemical can essentially poison any water it comes in contact with. This can include the water in your fish tank or any sort of water feature you include in a reptile enclosure.

At fox&toad, none of the tumbled stones we sell include lacquer finishes. The best way to test for a lacquer finish is to get a nail or other small, sharp object and scrape the surface of your stone. If small, typically clear, flakes come off of the stone, you’ve got lacquer.

If your polished stones have a traditional finish, they’re most likely aquarium safe rocks. Still, you should boil any rocks for 10-15 minutes before placing them in an animal’s enclosure.

But the polish on your rocks isn’t the only thing that can harm your pet.

What Polished Rocks are Safe for Aquariums?

When researching if you can put polished stones in a freshwater aquarium, you should consider what kind of rocks you have and if they contain any inclusions or added minerals that can harm your pet.

The post popular types of tumbled stones are quartz and jasper specimens. For the most part, these stones are aquarium safe, as they’re hard stones that have very little added mineral content. There are exceptions to the rule, though.

Bumblebee Jasper, for example, isn’t actually a Jasper. Instead, it’s a metamorphic rock that’s formed from various volcanic materials. Among those materials is sulfur, manganese oxide, realgar and orpiment - all arsenic-sulfide minerals. 

Bumblebee Jasper in its raw form can even harm humans if you ingest any of those arsenic-included minerals. That’s why you should always wash your hands after holding a raw version of this stone.

While a tumbled stone or pebble retains a polish that seals in that material, thus making it safe to handle, you still don’t want to risk exposing your pet to the possibility of the polish wearing off in time.

You also want to avoid any materials that look metallic - such as Pyrite, Copper or Chalcopyrite. These materials often add alkaline elements to water that can kill fish or animals that drink from it. Plus, many might have sharp edges that can hurt your pet if he or she brushes against them.

That said, we offer hundreds of various tumbled stones that you’ll love to look at, and your pet will love to live with.

Aquarium safe stones can include:

Polished stones to avoid in your aquarium:

  • Stones with heavy amounts of aluminum (Emerald, Garnets, Labradorite, Moonstone, Ruby, Sapphire, Topaz and Turquoise among others)
  • Asbestos and sulfur materials (Lapis Lazuli, Bumblebee Jasper, Malachite, Sulphur, Brimstone, Tiger Eye)
  • Lava Rock
  • Coal
  • Limestone (Can drastically impact your pH and hardness)
  • Dolomite

Rose Quartz, for example, can give a loving splash of pink to any environment. Tourmalinated Quartz gives the clean look of clear quartz with several dashes of black tourmaline throughout each stone. Apricot Quartz is a great way to give an orange and yellow look to your tank.

Amethyst is one of the most popular stones to add to aquariums - and we have a dozen or more types to choose from. These can range from light to deep purples with a whole range of colors in between.

Jasper is another great option for giving a more natural look to your pet’s home. 

Among the most popular Jasper polished stones for an aquarium are:

Another Jasper to avoid is Dalmatian Jasper, which contains heavy amounts of aluminum. 

These stones, and the dozens of other Jasper tumbled and polished stones we sell, provide a natural look to your pet’s environment, and give you something extra to observe when watching your friend in action.

You also want to research any stones you add to make sure their added minerals - such as Limestone - that could impact the PH and other water chemistry.

To be completely safe, you can attempt to create a mock setup with the stones in some water. If you're adding the stones to a terrarium, include some of your pets substrate in the water. Let the mixture sit for a couple days and perform a water test before adding them to your main setup.

Cleaning Polished Stones in an Aquarium

Perhaps the biggest issue you may have when adding tumbled stones to your aquarium is keeping them clean and shiny. In any wet environment, you’re going to have organic bacteria that grows. In most aquariums and terrariums, that means algae. This will happen even with generic aquarium rock or artificial plant add-ons.

While this won’t hurt the stones or your pet, it can hide some of the beauty of the polished stones you add to your fish tank. As algae grows, it will cling to the rocks in the tank, creating a hazy look and possibly dulling some of their colors. This isn’t a permanent stain on the stones. 

The easiest way to give the tumbled stones a “refresh” is to remove them from the tank and boil them for 10-15 minutes - while giving them a good scrub after. While it won’t remove all of the biofilm, it will clean them substantially. 

You don’t have to do this regularly, but it doesn’t hurt to complete the task whenever you see it’s needed. This is especially true in a freshwater tank, where you'll have fewer chemicals and additives added to the water.

While this list of aquarium safe polished stones is intended to help guide you in choosing the best, and safest, natural decorations for your aquarium and terrarium, it’s by no means a complete list of the only stones you can and can’t use in your enclosures.

Like with all things in life, the more research you do, the better prepared you’ll be to use aquarium-safe rocks. If you have a specific stone in mind that you’d like to use, thoroughly check on its contents, and potential inclusions, to make sure it doesn’t contain trace materials that could seep into the water. 

Even a little seepage can create a big problem. Remember, your pets lungs and nervous system is substantially smaller than yours. So a small amount of a bad mineral to you is equal to a big dose for him or her.

But you can minimize your risks by boiling any stones you plan to add, checking on the type of polish used to coat the tumbled rock and conducting a water test after letting the rocks sit in some water away from the aquarium.

If you do this, you can create a wonderfully natural environment for your pet with lots of colorful decoration — and a great place for you to observe their activities.

Feel free to contact us via email with any other questions you may have or if you need specific recommendations for the best polished stones to use in an aquarium.