The Best Rocks For Freshwater Aquarium - Aquascape in Style!

April 06, 2020

Best Rocks For Freshwater Aquarium

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 tanks. 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.

The Best 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.

Picture Name Sub-Type Best For Links
ADA Tank Supply Stones ADA Tank Supply WYSIWYG Stones Igneous - Granite Planted Tanks
Awesome Aquatic Ohko Dragon Stone Rock Awesome Aquatic Ohko Dragon Stone Rock Igneous - Granite Planted Tanks
GracesDawn Pine Bark Stone Graces Dawn Pine Bark Stone Igneous - Granite Planted Tanks
Lifegard Aquatics Petrified Stone Lifegard Aquatics Redwood Petrified Stone None - Petrified Wood Planted Tanks
Penn-Plax Deco Rock Penn-Plax Deco-Replicas Ornament Series None - Resin Cichlids
Seven Seas Seiryu Stone Seven Sea Supply Seiryu Stone Igneous - Granite Planted Tanks
Pisces Seiryu Rock Review Pisces Seriyu Rock Igneous - Granite Planted Tanks
Slate Rocks Small World Slate & Stone Rock Metamorphic - Slate Freshwater Tanks
Holey Rock Texas Holey Rock Sedimentary - Limestone African Cichlids

Third Planet Treasures Rock Third Planet Treasures - WYSIWYG Lava Rocks Igneous - Lava Rock Freshwater Tanks


1. ADA Tank Supply WYSIWYG Stones - For the Pro Aquascapers

ADA Tank Supply WYSIWYG Stones

We start off this list with high end aquarium rocks. These rocks offered by ADA Tank Supply 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.


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


  • Slow shipping times
  • Expensive

Best For - Planted Tanks

2. Awesome Aquatic Ohko Dragon Stone Rock - Great Rocks for Planted Tanks

Awesome Aquatic Ohko Dragon Stone Rock 

Dragon stone is one of the preferred aquarium rocks to use in Iwagumi Aquascapes. These rocks by Awesome Aquatics 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.

Like any preferred aquascaper rock, they do have a higher price tag.


  • Rocks do not alter pH or hardness
  • Great looking rocks


  • Price

Best For - Planted Tanks

3. Graces Dawn Pine Bark Stones - Unique Looking Rocks

Pine Bark Stones Review

If you are looking for a unique looking aquarium rock, check out these Pine Bark stones by Graces Dawn. 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. This particular seller only offers in the 5-7 lb rock range. 


  • Rocks do not alter pH or hardness
  • Amazing unique look


  • Availability
  • Not offered in large sizes

Best For - Planted Tanks

4. Lifegard Aquatics Redwood Petrified Stone - Made For You Aquascape Sets!

Lifegard Aquatics Redwood Petrified Stone Review

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!


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


  • It's wood versus stone - some purists may not be fans

Best For - Planted Tanks 

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

Penn-Plax Deco Rock Review

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.


  • Cheap
  • Easy to clean
  • Great for territorial fish


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

Best For - Cichlids 

6. Seven Sea Supply Seiryu Stone - A Budget Friendly Seiryu Stone

Seven Sea Supply Seiryu Stone Review

If you are looking to do a Seiryu hardscape without the Seiryu prices, take a look at these rocks from Seven Sea Supply. Seiryu stones are very popular in aquascaping and Freshwater Shrimp Tanks. These stones make very striking mountain like pieces when setup correctly. They will not alter your pH or hardness. The price of these sets are very reasonable compared to most Seiryu sellers. Due to the lower price, you do not get to select your rocks.


  • Very popular for hardscaping
  • Will not alter pH or hardness
  • Good price


  • Mixed set - you do not know exactly what you are getting

Best For - Planted Tanks 

7. Pisces Seiryu Rock - The Aquascaper's Choice

Pisces Seiryu Rock Review

If you want a step up from Seven Sea's stones, I would highly recommend Pisces Seiryu Rock. These are hand picked stones from the Pisces team. They are headquartered in Australia and one of the world's largest wholesalers of aquarium supplies. Because you are buying these direct from a wholesaler, you get a better price than purchasing similar at a specialty store. 

The actual product ratings for these stones have been impressive. I'm used to seeing mixed stone sets buyers get disappointed because the packages are mixed bags. Pisces really takes the time to pick out quality stones. You will not be disappointed in going with them!


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


  • Price

Best For - Planted Tanks 

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

Small World Slate & Stone Rock Review

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.


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


  • Easy to chip or break 

Best For - Freshwater Tanks 

9. Texas Holey Rock - Perfect for African Cichlids

Texas Holey Rock Review

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


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


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

Best For - African Cichlids 

10. Third Planet Treasures - WYSIWYG Lava Rocks

Third Planet Treasures Rock Reviews

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 WYSIWYG lava rocks by Third Planet Treasures is 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.


  • Large rocks
  • Lava Rock has multiple beneficial properties


  • Price
  • Slow shipping

Best For - Freshwater Tanks

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.

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.  


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