The Best Rocks For Freshwater Aquarium – 9 to Aquascape in Style!

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It seems like a great idea to just go out to your local pond or river and grab whatever rocks you find and add them to your tank. My advice is to not do that. This can be a recipe for disaster. Today’s post centers around the best rocks for a freshwater aquarium. There is a lot to consider before we drop that rock you found into your aquarium.

Rocks can alter the chemistry of our aquarium and have catastrophic results to our prized livestock. If you do not know what the rocks can do to your aquarium chemistry you can be headed to a world of hurt and heart break. 

In addition, rocks for freshwater aquariums can be cornerstones of your aquascape. Other times they are accents. They serve multiple purposes for us in aquariums. They offer protection and shelter for our fish and they are appealing to the eyes of the aquarium owner and their house guests.

Today’s post covers it all. I will go over the types or rocks used for freshwater aquariums then compile a list of the best rocks you can purchase online. In the posts there will be affiliate links where I may get a commission should you choose to make a purchase at no charge to you. With that disclosure provided, let’s go ahead and get started.

What to Look For When Purchasing A Rock for a Freshwater Aquarium

In general, the vast majority of freshwater fish and plants prefer softer water and lower pH. Knowing this fact, we want to avoid rocks that are high in calcium. Rocks high in calcium will alter the water chemistry of our aquarium. It will result in our water becoming hard. They also will alter the pH of the aquarium making our aquarium alkaline in nature. That is great for African Cichlids and Saltwater Tanks, but will be disastrous for most tropical fish we can purchase.

We need to break down rocks further to understand what makes a good freshwater aquarium rock. Let’s dive into the types of rocks.

The Three Types of Aquarium Rocks

We can separate freshwater aquarium rocks into three categories: igneous, sedimentary, and metamorphic rocks.

Igneous Rock

Black Lava Rock

Igneous rock is any type of crystalline or glassy rock. These are formed by the cooling and solidification of molten earth material. Aquarium rocks in our trade of this type would include dolerite, gabbro, granite, basalt, and lava rock.

Sedimentary Rock

Limestone Rock

Sedimentary rock are rocks that are formed by the accumulation or deposition of small particles and subsequent cementation. Aquarium rocks in our trade of this type would include marl, limestone, sandstone, breccia, conglomerate, and shale.

Metamorphic Rock

Slate Stone

Metamorphic rocks arise from the transformation of existing rock types. The original rock form was subjected to heat and pressure which cause physical or chemical change. Aquarium rocks in our trade of this type would include quartzite, dolomite, marble, schist, slate, and hornfels.

Aquarium Rocks That Alter Chemistry

Now that I explained the types of rocks, let’s talk about the aquariums rocks that can alter the chemistry of our tanks. We can separate them into two types. 

  • Aquarium Rocks that lower pH and soften water
  • Aquarium Rocks that increase pH and harden water

If we are looking to lower pH and soften our water, we want to use aquarium rocks like sandstone and basalt. If we are looking to increase pH and harden our water, we want to use aquarium rocks like marble and limestone

There are also rocks that serve functions with planted aquariums. For example, lava rocks can be used to fertilize aquatics plants. Granite is one of the safest rocks to use in an aquarium due to its neutral nature. It is also one of the heaviest.

9 Safe Rocks For Freshwater Aquarium

Now that we have a base understanding of rocks for freshwater aquariums, it’s time to talk about the best ones to buy. Below is a recommend list of the best freshwater aquarium rocks you can purchase online. I’ll go in more detail in my reviews of each.

In a hurry? I recommend Ohko Dragon Stone!

PictureNameBest ForLink
Editor’s Choice!
Ohko Dragon Stone
Ohko Dragon Stone

Planted Tanks

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Best Value
Black Mountain Seiryu Stone
Black Mountain Seiryu Stone

Planted Tanks

Click For Best Price
Budget Option
Black Lava Rock
Black Lava Rock

Planted Tanks

Click For Best Price
Traditional Seiryu Stone Traditional Seiryu Stone

Planted Tanks

Click For Best PriceBuy On Glass Aqua
Premium Pick!
Buceplant WYSIWYG Stones
Buceplant WYSIWYG Stones

Planted Tanks

Click For Best Price
Lifegard Aquatics Redwood Petrified Stone Lifegard Aquatics Redwood Petrified Stone

Planted Tanks

Buy On Amazon
Penn-Plax Deco-Replicas Ornament Series Penn-Plax Deco-Replicas Ornament Series

Cichlids

Buy On Amazon
Small World Slate & Stone Rock Small World Slate & Stone Rock

Freshwater Tanks

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Texas Holey Rock Texas Holey Rock

African Cichlids

Buy On Amazon

The 9 Best Rocks For Freshwater Aquarium (2022 Update)

Let’s take a closer look as to why these rocks stand out so much!

1. Ohko Dragon Stone Rock – Great Rocks for Planted Tanks

Editor's Choice!
Ohko Dragon Stone

Editor's Choice

Ohko is the premier aquascaping rock today. Granite based with amazing shapes and selection

Buy on Buce Plant Buy on Glass Aqua

Ohko Dragon Stone is one of the preferred aquarium rocks to use in Iwagumi Aquascapes. These rocks are not only beautiful, they are also natural in nature. They will not alter your pH or hardness being granite based. They will look fantastic in any planted tank setup. They are full of holes, nooks and crannies making them very good rocks for natural shelter for your fish.

These are the hot rocks for pro aquascaping projects these days. Check out the video above from BucePlant to see how amazing they look. Like any preferred aquascaper rock, they do have a higher price tag.

Pros

  • Rocks do not alter pH or hardness
  • Great looking rocks
  • Lots of sizes available

Cons

  • Price

Best For – Planted Tanks

2. Black Mountain Seiryu Stone – Best Value In Unique Looking Rocks

Best Vaue
Black Mountain Seiryu Stone

Best Value

With an amazing black and white contrast, black mountain is an excellent choice for any aquascape. It is reasonably priced!

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If you are looking for a unique looking aquarium rock, check out Black Mountain Seiryu Stone. The unique white veins really pop in an aquascape. They will not alter your pH or hardness so you can add them to any aquarium setup. These rocks are hard to find so be on the look out if you like them and want to buy one. The great thing from buying from our link is that Buce sells super high quality Black Seiryu and in packs up to 30lbs! 

Pros

  • Rocks do not alter pH or hardness
  • Amazing unique look
  • Lots of sizes available

Cons

  • Availability
  • Price

Best For – Planted Tanks

3. Black Lava Rock – A Great Budget Aquascaping Rock

Budget Option
Black Lava Rock

Budget Option

Great choice for budgets. Won't alter your chemistry and provides housing for beneficial bacteria

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Quality lava rock is hard to find online. It’s pretty common to see listings of lava rock being used as biomedia or fireplaces. This makes sense given they are great for housing beneficial bacteria and are great stones for fire places. This does limit what you can buy on online though.

When it comes to aquarium lava rock these Black Lava Rocks by BucePlant are exactly what we are looking for. These are large rocks with unique shapes unlike what you will find at most pet stores. If you are looking to quality lava rock, check out their store and selection.

Pros

  • Black color works well with aquascapers
  • Price
  • Lava Rock has multiple beneficial properties

Cons

  • Not as pretty as the major aquascaper rocks

Best For – Freshwater Tanks

4. Traditional Seiryu Rock – The Aquascaper’s Choice

Traditional Seiryu Stone

A go to classic. Highly recommended for Iwagumi aquascapes

Buy On Buce Plant Buy On Glass Aqua

If you want a pro quality aquascaping rock, but the Ohko is out of your budget, I would highly recommend Buce Seiryu Rock.  Seiryu is the godfather of all aquascaping rocks. These are hand picked stones from Buce. With their excellent customer service and high quality reviews, you can’t go wrong with them!

You will not be disappointed in going with them! Great details and texture comes with these rocks.

Pros

  • Great rock specimens
  • Great reviews and testimonials
  • Hand picked stones

Cons

  • Price

Best For – Planted Tanks 

5. BucePlant WYSIWYG Stones – For the Pro Aquascapers

Premium Pick
Buceplant WYSIWYG Stones

The Finest Available Online

Buceplant offers the premium stones online. Showpiece What You See Is What You Got (WYSIWYG) stones. Get your centerpiece today!

Click For Best Price

We start off this list with high end aquarium rocks. These rocks offered by BucePlant are what we call in the industry What You See Is What You Get (WYSIWYG) rocks. This seller lists individual rocks or sets of rocks for you to purchase and you get the exact rocks in the picture. This is the best way to get large aquarium rocks for aquascapes if you are looking to do big projects.

In my mind, WYSIWYG vendors are the sellers to go to if you are looking for a large display stone. These are excellent for planted tanks and highly recommended if they are within your budget.

Pros

  • You get exactly what you see in the photo (WYSIWYG)
  • Large aquarium rocks available
  • High quality rocks

Cons

  • Limited quantities
  • Expensive

Best For – Planted Tanks

6. Lifegard Aquatics Redwood Petrified Stone – Made For You Aquascape Sets!

Great For Beginners
Lifegard Aquatics Redwood Petrified Stone

A complete set done for you. This is a great choice for someone completely new to aquascaping

Buy On Amazon

Are you looking for a done for you aquascape set? If so, the Lifegard Aquatics Petrified Wood Sets are right up your ally. These aquarium rocks are sold in packages for specific tank sizes. All you do is order the place for your aquarium and you are good to go. No need to guess or pick rocks. These sets use pertified wood instead of stone. As a result, the look is very unique for your aquascape.

Lifegard also offers another variant called the Klondike Petrified Stone set if you are looking for a different shade or color. I love these sets for first time aquascapers. It is wood versus stone, which may bother a purist, but not a problem for a newcomer. The price is pretty reasonable as well!

Pros

  • Will not alter pH or hardness
  • Done for you sets
  • Unique look

Cons

  • It’s wood versus stone – some purists may not be fans

Best For – Planted Tanks 

7. Penn-Plax Deco-Replicas Ornament Series – Great for Territorial Fish

Penn-Plax Deco Rock

Simple and designed for Cichlids. These rock provide shelter for your territorial fish

Buy On Amazon

Penn-Plax Deco-Replicas Ornament Series are resin ornaments that resemble natural granite. They are great for territorial fish like cichlids. Each aquarium rock acts like an individual home or condo for your fish. Because they are resin based, so they do not affect your water chemistry and are very easy to clean due their smooth outer surface. They are also very easy to stack and create a community of homes. 

The thing I do not like with these rocks is they are rough on the inside. This is due to their resin makeup. The resin has been smoothed out on the outside but not on the inside. This leads to rough and sharp edges inside the structure. This does not make them safe for delicate species like Betta Fish. You can make them smooth with a file, but given their price point it’s probably better to look at another product if you have delicate fish.

Pros

  • Cheap
  • Easy to clean
  • Great for territorial fish

Cons

  • Rough on the inside – not safe for delicate fish like Bettas

Best For – Cichlids 

8. Small World Slate & Stone Rock – Slate for a Great Price

Small World Slate & Stone Rock

Great price and selection. Small world offers an affordable solution for quality aquarium slate

Buy On Amazon

These Slate Aquarium Rocks by Small World are an amazing deal. The product pictured above are the 5-7 inch stone sets. These are high quality slate pieces sourced from the USA. Small World Slate and Stone is a small family run business and their customer service is top notch.

Slate will not alter your pH or hardness. They are great for Aquascaping and for creating caves and structures. They are also great for reptiles since they hold heat well. Slate is one of the most popular stones for garden and pond hardscaping.

Slate is easy to break or crack. Be very careful with handling the stones as they can chip easily.

Pros

  • Good price
  • Will not alter pH or hardness
  • Soured from the USA and small business owned

Cons

  • Easy to chip or break 

Best For – Freshwater Tanks 

9. Texas Holey Rock – Perfect for African Cichlids

Great For African Cichlids
Texas Holey Rock Natural Limestone

With its ability to raise pH and hardness, this rock is an excellent choice for African Cichlids

Buy On Amazon

If you own African Cichlids, these limestone rocks are perfect for them. Texas Holey Rock has several benefits for African Cichlids. Being made of calcium carbonate, these rocks buffer pH and hardness, which solves your aquarium water chemistry issues with Africans. The holes are great for shelter and curbs aggressive in your freshwater tank.

These rocks are sourced locally in Austin, Texas. The team who selects these rocks take care to find quality specimens for aquarium usage. The Company was built by a Cichlid tank owner who understands the need for quality hardscaping.

Give their limestone makeup, these rocks are only appropriate for fish that need a higher pH or hard water. The white appearance is also not for everyone. You can mitigate the white look by using low light aquarium plants like Java Fern, which easily attach to these rocks. 

Pros

  • Buffers pH and hardness for African Cichlids
  • Hand picked selection
  • Holes are great for shelter

Cons

  • White appearance not for everyone
  • Only for fish that need hard water and higher pH

Best For – African Cichlids 

The Best Rock For Freshwater Aquarium – Our Expert Pick

I listed a number of aquarium rock selections. Which one is best for you? I’m going to split these in several categories and explain.

FAQS

What Rocks Are Safe For Freshwater Aquarium?

The safest rocks are ones you can purchase at a pet store, local fish store, or online. That being said, the best rocks to use are Ohko dragon stone, Seiryu Stone, and Lava Rock. You can also use rocks like slate for building levels and Holey Rock for setups that require hard water or higher pH.

Can You Put Any Kind Of Rock In A Fish Tank?

No. You cannot just put any rock in a fish tank. Some rocks will alter the chemistry of the water like it’s pH or hardness, which can have negative affects on your fish and plants. Rocks collected from outside or rivers may also contain organic material, which may die off and cause ammonia spikes. It’s best to purchase your rocks from a reputable pet store whether in person or online.

Can Live Rock Be Used In Freshwater?

No. Live rock is rock that is either pulled from the oceans or grown aquaculturally to be used in saltwater tanks. They contain saltwater bacteria and organisms, which would die off if placed in a freshwater tank.

What Rocks Raise the pH in the Aquarium?

Rocks that are made of calcium carbonate like limestone will raise the pH in an aquarium. These rocks are ideal for fish that prefer higher pH and hardwater like African Cichlids.

Conclusion – Best Rocks for Freshwater Aquarium

Aquarium rocks can really be striking backdrops in your fish tank when you find the rest specimens. I hope this post helped you find what you were looking for. If you have any questions, please leave a comment below. Thanks for reading.  

by Mark

Mark is the founder of Aquarium Store Depot. He started in the aquarium hobby at the age of 11 and along the way worked at local fish stores. He has kept freshwater tanks, ponds, and reef tanks for over 25 years. His site was created to share his knowledge and unique teaching style on a larger scale. He has worked on making aquarium and pond keeping approachable. Mark has been featured in two books about aquarium keeping - both best sellers on Amazon. Each year, he continues to help his readers and clients with knowledge, professional builds, and troubleshooting.

5 COMMENTS

  1. Lava rocks give awesome look in an aquarium. You can use lava rocks undoubtedly in yours. But you cannot put it in your aquarium directly, you have to prepare it before placing it. So, follow the steps below:
    You can clean them with fully clear water and make them clean. But we will mention some more useful methods with you. We can wash the rocks for 30 min with clean water, then it will be clean to use in the aquarium.
    You can boil the lava rocks in water for 30 minutes. It will remove all dirt and clean the potential diseases from the rocks. After boiling them, wipe them with a clean towel, then we have to cool them for one hour. Then we can use them in aquariums.
    We can also use bleaching powder. We can use 1:10 portion in water and keep the rocks in the solution for 24 hours. They will be clean and disinfectant. Then we can use them for aquariums.

    Reply
  2. Hi I was given quite a lot of rock which white with lots of hole it was in a Malawi cichlid tank beautifully clean
    Some nice big pieces will this be alright in a tropical tank
    Cheers Bill G.

    Reply
    • Hi Bill

      That might be Texas Holey rock. Holey rock is made of limestone and would increase your pH. It is best suited for African Cichlids. It won’t be suited for most freshwater tropical fish set-ups.

      Reply

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