Ever dream of building a lava rock aquarium? Lava rocks are a great way to maintain your aquarium and make for some of the prettiest and best fish tanks. Not only because lava rock looks awesome but the fish will love them. If you add them correctly and prepare beforehand with some basic maintenance, tasks such as proper cleaning or changing water often enough then adding carved lava rock to an aquarium will greatly benefit both fish keepers and fish alike.
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Creating a Lava Rock Aquarium In Your Home
Adding a variety of lava rocks is a great way to add eye-catching aesthetics and structure to your aquarium. They come in all shapes, sizes, and colors so there’s something for everyone! Learn how you can prepare them safely before adding them into the mix with this guide.
How To Prep Lava Rocks For An Aquarium
You have decided to create a lava rock aquarium but want to do it properly?
Lava rocks are a great addition to any aquarium, but they can’t just be thrown in. Before adding lava rocks make sure that you clean them with an approved fish tank brush and remove all bacteria from the tank so animals don’t get sick or plants grow too poorly because of pollution caused by these foreign substances.
Caring For A Lava Rock Aquarium
Very importantly, you will want to ensure that your lava racks are completely cleaned of any foreign debris and dirt buildup. Dirty lava rocks can present health hazards if placed in a tank for your plants and pets.
Here are a few steps to make sure your lava rocks are safe for an aquarium:
1) Scrub and Wash Lava Rocks Thoroughly
To prepare lava rock, gently add the lava rocks to a bucket of water and fill it up as high as possible. Proceed by scrubbing them completely and be sure to get into the tiny cracks and caves. This will help wash off all particles from the rocks. If your lava rocks are very dirty, feel free to change out the dirty water for fresh as needed.

Once you have scrubbed and cleaned your lava rocks, like any aquarium decorations, it will be time to let them dry. Simply leave them in a dry warm environment for 24 hours and they will become completely dry. If you are impatient, using a hairdryer to speed the process is acceptable.
2) Disinfecting Lava Rock For Use In an Aquarium
Once your lava rock has gotten a full bath and is cleaned, it is time to disinfect. To rid the carved lava rock additions to your aquarium, you will want to simply boil the entire lava rock to kill any bacteria that could hurt your fish.
Fill a large pot with water and add the rocks and place a lid on top, leaving a little room in the pot as to not boil over. After about 10 minutes, you will have bacteria-free lava rocks. The rocks will be very hot, so take precautions such as oven mitts to handle them.
Do not boil the rocks any longer than 30 minutes, as the rocks will begin to erode under the stress of heat. Once the rocks have cooled, it is time to add them to the aquarium.
Never add hot rocks immediately to a fish tank’s water as the intense heat can break the rock as well as create unstable water temperatures.

3) Alternative Lava Rock Disinfecting
At times, you may have a large lava rock that will not fit in a standard pot to boil. If this is the case, you can use a bleach mixture. At times chemical disinfectants can deteriorate certain rocks, so be sure they won’t fall apart before using this method to clean your lava rocks.
Take an empty container and add 10 parts water to 1 part bleach, ensuring you do not exceed the bleach’s recommended dosage. Place the rocks in the bleach solution for 24 hours. From there, you will want to then rinse and scrub them again. You may have to re-clean the rocks a couple of times after the bleach mixture to remove any leftover chemicals.
Once clean they can be added to the aquarium with a bit of planning before you add them to a fish tank.
Prepping Your Lava Rock Aquarium
Before you add any rocks to your aquarium, you will want to make minor adjustments to the aquarium’s layout.
Do not forget about these simple rules when preparing and adding a layer of lava rock into an empty tank.
- Level The Aquarium – It is important to have your tank flat before adding the carved lava rock. This way, you will be able to evenly distribute their weight and they won’t fall over easily. Lava rocks are heavy and could benefit from a solid, and level base to sit on.
- Styrofoam Sheets – One way to keep your new fish tank looking good is by using Styrofoam sheets. If you’re going with a glass-based setup, these should be applied before adding in any lava rocks or other pieces of decor!
- Acrylic Aquariums – If you want to prevent your acrylic aquarium from getting scratched from lava rock, make sure there’s some clean sand under the lava rocks. About an inch of sand will allow for the rocks to settle and not scratch the surface of the aquarium.
Adding Lava Rock to Your Aquarium Is a Good Idea
What are the hidden benefits of adding lava rock to your aquarium is a question we get asked frequently. Below are some highlights as to why you should consider adding lava rock to your fish habitat.
Lava Rocks Improve Water Clarity
There are many hidden benefits when you add stones like lava rocks to planted tanks. You might be wondering what the most important hidden benefits of adding lava rocks to your aquarium are?
One of the hidden benefits, according to many hobbyists is that these stones will help clean water in fish tanks and improve clarity. This type of rock decoration contains elements that can cause clear water to appear more vibrant.
Water quality from ph levels and removing nitrates will create an ideal living environment for aquarium use and provide natural decoration is one of the key benefits.
Does Lava Rock Affect PH?
In general, most lava rock acts like basalt but with bubbles in it. It’s fairly inert on its own and shouldn’t affect the ph. However, depending on where you get your volcanic rocks from other deposits may have been mixed into them which could influence their effect on ph levels.
If an area has rich groundwater deposits, carbonates can form. When introduced into water, the carbonates can raise ph drastically, which is rare.
Provides a Complete Aquatic Environment
Lava rocks are a great way to provide your small fish with more porous caves. These porous rocks will act as the perfect hideouts as the holes add depth, and offer animals safety, oxygen, and beneficial denitrifying bacteria to reduce high ph and cleaner water.
Lava Rock Is Aesthetically Pleasing
Larger lava rock formations work just as well for a lava rock aquarium because not only do you get more options for where fish like Bettas, Guppies, and African Cichlids can rest, but lava rocks can also create a beautiful environment that any fishkeeper can enjoy.
Anchors Plants Securely
A little bit of plant life goes a long way in an aquarium and adds character. A lava rock aquarium is a great tank idea for anchoring your plants so they can provide clean air and nutrients, while also being effective at tying them down to prevent vertigo-inducing swaying!
Beneficial Bacteria Lowers Aquarium Water Nitrate Levels
Not to be confused with live rock, lava rocks are covered by holes and pores that have beneficial bacteria, which is called denitrifying.
These microorganisms help filter out the bad nitrogen to make sure your plants get all they need for growth!
Tips When Buying Carved Lava Rock
- A lava rock aquarium is a great place for small fish to hide, but they’re not so good if you have a lava rock aquarium with larger species because the sharp edges can cause them harm.
- Avoid purchasing lava rock pieces that have jagged points on all four sides – these types of decorations will be dangerous in your tank and could even kill off some precious inhabitants.
- Lava rocks are not all the same! Picking up a cleaner bag with less dirt and particles will help you save time and water when cleaning them. You’ll also be able to wash and clean your fish tank easier in the long run.
How To Add Lava Rocks Into an Aquarium
You do not want to simply drop lava rocks into a fish tank. They are big and bulky so placement is important, plus you want the tank decorations to look great.
Don’t Scratch, or Stack Lava Rocks Against the Glass
Lava rocks are strong and heavy, so be careful with these rocks as you stock the tank. You never know how much weight your glass aquarium can handle!
Keep them a safe distance from the aquarium glass so as they settle, they will not land against the walls of the tank.
Unsecured lava rocks are not always safe around the glass of an aquarium. One way to make them less likely to fall is by gluing the pieces together with silicone, which will not harm you or your fish’s space in any way.
Use smoother aquatic decorations closer to the glass to buffer the sharp edges of the lava rock itself. Something I find useful is using driftwood and carpet plants closer to the tank walls.
Any smooth natural decorations look great when they surround the lava rock.
Summing Up Lava Rock Aquarium Benefits
It’s never been easier to create a beautiful and unique aquarium for your home. With the right equipment, supplies, and lava rocks you can have an ideal environment in which to watch your favorite fish swim around!
If you just got some new lava rocks and need help getting them clean or setting them up in your tank, we’ve got all of the steps laid out above. Follow these simple directions and soon enough it will be time to enjoy watching your aquatic friends live happily ever after in their natural habitat!