Best Rocks For Freshwater Aquarium – Reviews And Guide

Tankarium is reader-supported. We may earn a small commission through products purchased using links on this page.

Think about the last time you saw a beautifully aquascaped tank. It could be something you saw on Pinterest while browsing for home décor inspiration, or maybe it was in a magazine. No matter where you encountered it, chances are that rocks were a big part of what made the display so appealing. Rocks seem to do everything from adding visual interest to creating hideaways for fish!

So, given the many aesthetic and practical benefits of using rocks in an aquarium, we’ve compiled a list of some of the best rocks for freshwater aquariums. We’ll talk about what to look for in aquarium rocks, and offer tips on choosing the best rocks for your tank. Then, we’ll move on to our top picks for your freshwater aquarium.

Without further ado, let’s get started!

Comparison Table of the 7 Best Aquarium Rocks

IMAGE

Polished Mixed Color Fish Tank Stones, 18lbs

BRAND

Polished Mixed Color Fish Tank Stones, 18lbs

DETAILS

  • Package Dimensions: 13.82 x 10.47 x 3.46 inches
  • Item Weight: 18.46 pounds
  • Manufacturer: CFKJ

Pricing

Lifegard Aquatics Dragon Ohko Aquascaping Rocks

BRAND

Lifegard Aquatics Dragon Ohko Aquascaping Rocks

DETAILS

  • Manufacturer: Lifegard Aquatics
  • Country of Origin: China
  • Rock Weight: 4.6 pounds
Exotic Pebbles Polished Mixed Gravel

BRAND

Exotic Pebbles Polished Mixed Gravel

DETAILS

  • Manufacturer: Exotic Pebbles
  • Product Dimension: 10.75 x 1.75 x 8 inches
  • Product Weight: 5 lbs
Balacoo Volcanic Lava Rocks for Fish Tanks

BRAND

Balacoo Volcanic Lava Rocks for Fish Tanks

DETAILS

  • Manufacturer: Balacoo
  • Product Dimensions: 2.36 x 2.36 x 2.36 inches
  • Product Weight: 15.87 Ounces
Pure Water Pebbles, 5lbs, Salt and Pepper

BRAND

Pure Water Pebbles, 5lbs, Salt and Pepper

DETAILS

  • Theme: Space
  • Brand: Pure Water Pebbles
  • Color: Black and White
  • Material: Acrylic
  • Item Weight4.75 Pounds
  • Product Dimensions: 3.5 x 8 x 11 inches
Spectrastone Special Turquoise Aquarium Gravel

BRAND

Spectrastone Special Turquoise Aquarium Gravel

DETAILS

  • Manufacturer: Estes Gravel Products
  • Product Dimensions: 10 x 7.25 x 1.5 inches
  • Product Weight: 5 Pounds
Abnaok Aquarium Stacked Stone Rock Decor

BRAND

Abnaok Aquarium Stacked Stone Rock Decor

DETAILS

  • Manufacturer: Abnaok
  • Package Dimensions: 6.89 x 4.49 x 4.17 inches
  • Package Weight: 9.59 Ounces

Types of Rocks To Avoid

Before we get into our list of the best rocks for freshwater aquariums, it’s important to discuss the types of rocks you should avoid using in your tank. Many of these have harmful or undesirable qualities that may make them harmful to your fish or plants, or simply not ideal for use in an aquarium. Here are some types of rocks we recommend avoiding:

Rocks That Alter Tank pH

Unless you’re making a specific effort to raise or lower the pH of your aquarium water, you’ll want to avoid using rocks that will have this effect. The most common type of rocks that can raise your tank’s pH include:

Chemically speaking, these rocks are all fairly similar. They’re all made of calcium carbonate, which is a known pH buffer. This means it can help stabilize an aquarium’s pH by absorbing excess acids or bases. However, this also means that these rocks have the potential to raise your tank’s pH if they are not properly sealed.

If you decide to use one of these rocks in your aquarium, test your water regularly. It is also a good idea to test your rock’s reactivity before adding it to your tank. A simple method is adding a few drops of vinegar to the rock’s surface. If the rock fizzes or bubbles, it’s a clear indication that it will raise your tank’s pH.

Rocks With Sharp Edges

black rocks

Many hobbyists use rocks with holes and crevices to provide good fish hiding spots. While nooks and crevices are good, you’ll want to make sure that these do not come at the expense of your fish’s safety. Put simply, avoid using rocks with sharp or rough edges, such as slate rock.

Rocks with sharp edges can damage your fish’s fins, scales, and skin. In some cases, these injuries can become infected, leading to serious health problems for your fish. Secondary infections often occur due to physical injuries, and these can be very difficult (and expensive) to treat.

To avoid this, inspect your rocks carefully before adding them to your tank. If you see any sharp edges, either file these down or choose a different rock.

Rocks That Have Been Used In Medicated Tanks

When I first started fishkeeping, one of the biggest mistakes I made was adding rocks that had been used in a medicated tank to my display aquarium. While I thought I had thoroughly cleaned the rocks, it turns out traces of medication can linger on surfaces for months. The result? Almost every fish in my new tank displayed signs of stress within a week.

I was fortunate because the concentration of the medication was low enough that it didn’t cause any serious health problems for my fish. However, this experience taught me an important lesson: always research where your rocks came from before adding them to your tank.

betta channoides tank
Image Source: www.instagram.com

In general, you’ll want to avoid using rocks that have come from tanks that were medicated with copper-based medications. While these are effective at treating certain diseases, they can be very harmful (and even fatal) to fish. If you’re unsure whether the rocks you’re considering have been used in a medicated tank, your best bet is to err on caution and choose something else.

Now that we’ve covered what to avoid, let’s take a look at how you can choose the right aquarium rocks for your tank.

Buyers’ Guide: What to Look for in Aquarium Rocks

When choosing rocks for your freshwater aquarium, there are a few key factors to consider. Here are a few things to keep in mind when shopping for freshwater rocks:

Chemical Composition

Natural rocks come with different chemical compositions, so it is vital that you choose something compatible with your needs. For example, limestone rocks are high in calcium carbonate. This makes them a good choice for cichlid tanks as they require a higher pH. But those who need to keep their tank water soft might want to avoid these.

Because compatibility is crucial, it is always best to do your research before introducing new rock types to your tank. This may be less important if you’re using plastic or inert rocks that don’t alter your water chemistry. But if you’re using real rocks, make sure to test your water regularly after adding them to your tank.

The same rule applies to rock substitutes such as crushed coral or aragonite sand. These materials can also change your water chemistry, so it’s important to know how they might affect your fish.

Aesthetic Appearance

Fish Tank Plants Decor

Let’s move on to something a little more fun: how your rocks look in your tank! After all, one of the main reasons people use decorative rocks in their tanks is to create a stunning display.

Before you choose your rocks, it’s a good idea to know how you want your tank to look. Do you want accent pieces that contrast with your gravel? Consider opting for large rocks that have amazing shapes. Looking to create a disco-themed setup with tons of assorted colors? Smaller rocks that pack a visual punch might be more your style.

As you browse through different rocks, having a picture of your dream aquarium in mind can be helpful. This will help you zero in on the right rocks for your setup. Whether your dream setup involves a piece of petrified wood or gravel with a deep black color, focusing on the look you want to achieve can help make your decision easier.

Size and Weight

The next thing on our list is size. Put simply, your tank size determines how many pieces of rocks you can have in your aquarium, as well as the size of those rocks. To understand why this is the case, picture a 10-gallon tank filled to the brim with large pieces of rocks. Not only would this make your aquarium look cluttered, but it could also put too much weight on the tank.

To prevent an unfortunate accident, make sure you know the dimensions of your tank and the weight limit before adding larger rocks. And with aquarium rocks coming in such a large variety of shapes, we’d recommend weighing your rocks to be sure you’re not dealing with unexpectedly heavy rocks or pieces. A simple kitchen scale can help you do this easily.

At the end of the day, larger pieces have an advantage over smaller ones: they’re less likely to be eaten by your fish. They also make better homes for beneficial bacteria due to their larger surface areas. However, these benefits must be weighed against the potential risks of having too much weight in your tank. Once again, it all comes down to finding the right balance for your aquarium.

Safety

Lastly, safety is always a concern when adding new items to your aquarium. Do your research and identify safe rocks for your entire tank – not just your fish. This is especially important if you have shrimp or other invertebrates, as some rocks can release toxins that can harm or kill them.

If you’re opting for natural stones, get your rocks from a reputable source. And if you’re opting for artificial rocks, check to make sure that they’re made of 100% safe and non-toxic materials. It’s easy to go wrong by choosing something that looks safe but is actually harmful to your fish, so please do your homework and err on the side of caution.

When it comes to freshwater aquarium rocks, you can never be too safe. But if there’s one reminder we can leave you with, it’s this: the best rocks for your aquarium are the ones that strike the perfect balance between meeting the needs of your fish and achieving the look you want for your dream setup. Never put appearance before safety – trust us, it’s not worth it.

Great! You now know better what to look for when choosing rocks for your freshwater aquarium. Let’s move on to our reviews of the best rocks for freshwater aquariums, shall we?

7 Best Aquarium Rocks For Glass And Acrylic Tanks

1. Polished Mixed Color Fish Tank Stones, 18lbs

Polished Mixed Color Fish Tank Stones, 18lbs
  • Package Dimensions: 13.82 x 10.47 x 3.46 inches
  • Item Weight: 18.46 pounds
  • Manufacturer: CFKJ

Here’s the deal – 18 lbs of rocks seems like a lot. But these polished stones come in such a beautiful variety of natural colors that you will want to use them all. And with each rock measuring between 0.61 inches to 1.18 inches, these mid-sized rocks will have you feeling like you have an endless supply.

These rocks are also polished to perfection. So, if you’re looking for a more refined look in your fish tank, these are the rocks for you. Plus, polishing does a great job of evening out the rough surfaces and jagged edges one might find in rocks from nature. And since smooth edges go a long way in keeping fish safe, these premium stones are a big win in our books!

The only potential downside to these rocks is that they might prove too large for tanks under 10 gallons in size. Some reviewers attempted to use these as top layer rocks in smaller tanks and found that the size was just too overwhelming. But, if you have a larger tank, these rocks should work perfectly.

PROS

  • Comes with 18lbs of rocks
  • Polished to perfection
  • Eases rough surfaces and jagged edges

CONS

  • May be too large for smaller tanks

2. Lifegard Aquatics Dragon Ohko Aquascaping Rocks

Lifegard Aquatics Dragon Ohko Aquascaping Rocks
  • Manufacturer: Lifegard Aquatics
  • Country of Origin: China
  • Rock Weight: 4.6 pounds

Iwagumi-style aquascapes have become increasingly popular in recent years, and for a good reason. These minimalist landscapes are stunning to look at and relatively easy to maintain. The key to creating a successful Iwagumi-style aquascape is choosing the right stones, and that’s where Lifegard Aquatics Dragon Ohko Aquascaping Rocks come in.

Dragon Okho rocks come with lots of natural holes, nooks, and crevices, making them perfect as a natural refuge for small fish. Their organic shapes also add a sense of movement and flow to your aquascape. The best part? These all-natural rocks are completely inert and won’t affect your water chemistry. Rest assured, your fish will be safe and healthy in their new home.

One potential downside of these rocks is that they have rough edges that can cause rips and tears in your fish’s fins. If you plan to use these rocks in a freshwater aquarium, I recommend rounding off the edges with a hammer or file. Dragon Okho rocks also come at a premium price tag. However, given their unique shape and size, I think they’re worth the investment.

PROS

  • Natural holes provide fish refuge
  • Organic shapes add movement and flow
  • Inert and won’t affect water chemistry

CONS

  • Jagged edges can injure fish
  • Premium price

3. Exotic Pebbles Polished Mixed Gravel

Exotic Pebbles Polished Mixed Gravel
  • Manufacturer: Exotic Pebbles
  • Product Dimension: 10.75 x 1.75 x 8 inches
  • Product Weight: 5 lbs

Looking for something that’s both beautiful and easy to maintain? Check out Exotic Pebbles Polished Mixed Gravel. The gravel is composed of natural stones that have been polished for a smooth look and feel. Measuring 3/8ths of an inch in size, the gravel is small enough to prevent fish from swallowing it and large enough to provide good filtration.

The natural colors of the stones are muted and subdued, making them a good choice for those who want a natural look in their aquarium. Speaking from personal experience, these pebbles made my tank look sophisticated and inviting. One five-pound bag of Exotic Pebbles Polished Mixed Gravel could adequately cover the floor of a 55-gallon tank, making it a great value for the price.

If you’re looking for an attractive and low-maintenance option, I highly recommend Exotic Pebbles Polished Mixed Gravel. However, it is important to boil these pebbles before you use them as they are covered in a layer of wax. This is good practice for any gravel you use in your aquarium, but especially important for stones that may leech chemicals or bacteria into your tank

PROS

  • Attractive and natural looking
  • Low maintenance
  • Good value for the price

CONS

  • Must be boiled before use

4. Balacoo Volcanic Lava Rocks for Fish Tanks

Balacoo Volcanic Lava Rocks for Fish Tanks
  • Manufacturer: Balacoo
  • Product Dimensions: 2.36 x 2.36 x 2.36 inches
  • Product Weight: 15.87 Ounces

Lava rocks are seen as great natural options for freshwater aquariums because they’re inert, have relatively few jagged edges, and look great in most setups. These lava rocks from Balacoo stand out among the many different options on the market because of their unique red hue.

Not only will these rocks add color and contrast to your aquarium, but they can also act as a natural filtration system. Lava rocks are highly porous and help remove toxins and impurities from your water. This can be a great way to reduce your overall maintenance burden.

The only potential downside of these rocks is that they’re a little smaller compared to other options on the market. If you have a smaller tank, these will work perfectly. But if you’re thinking of using them in a larger tank, you may want to look for something else.

PROS

  • Inert and won’t affect water chemistry
  • Highly porous and great for natural filtration
  • Attractive red hue

CONS

  • Smaller size compared to other options

5. Pure Water Pebbles, 5lbs, Salt and Pepper

Pure Water Pebbles, 5lbs, Salt and Pepper
  • Theme: Space
  • Brand: Pure Water Pebbles
  • Color: Black and White
  • Material: Acrylic
  • Item Weight4.75 Pounds
  • Product Dimensions: 3.5 x 8 x 11 inches

Pure Water Pebbles’ Salt and Pepper gravel is a beautiful and unique option for those who want their aquarium to make a statement. The black and white gravel is coated with an acrylic resin that gives its colors an intense vibrancy. The acrylic coating is also non-toxic and colorfast, making it safe for use in freshwater aquariums.

This gravel is perfect for those who want to create a dramatic look in their freshwater aquarium setup. The black and white contrast is eye-catching and really makes your fish and plants pop. I love how this accent substrate looks in my tank, and I especially appreciate Pure Water Pebble’s reputation for creating safe, non-toxic products in various colors.

One major drawback for most reviewers is that the acrylic coating may not be as colorfast as advertised. This problem is more apparent when it comes to other products, such are pebbles in green or pink colors. However, this hasn’t been a reported issue among its Salt and Pepper gravel users, who, for the most part, are very satisfied with its look and quality.

PROS

  • Intensely colored
  • Safe for use in freshwater aquariums
  • Non-toxic and colorfast

CONS

  • Colors may fade over time

6. Spectrastone Special Turquoise Aquarium Gravel

Spectrastone Special Turquoise Aquarium Gravel
  • Manufacturer: Estes Gravel Products
  • Product Dimensions: 10 x 7.25 x 1.5 inches
  • Product Weight: 5 Pounds

Looking for something a little different than your typical aquarium substrate? The Spectrastone Special Turquoise Aquarium Gravel is a great option. The bright turquoise color may not be for everyone, but we can picture it looking perfectly at home next to some brightly colored fish. Why opt for the conventional when you can add a big splash of color and let your creativity go wild?

These gravels also come with a non-toxic coating. When it comes to aquarium gravel, the last thing you want is something that will leach harmful chemicals into your water. This is a common problem with painted gravel, but the Spectrastone Special Turquoise Aquarium Gravels make sure that’s not an issue.

The one potential downside of these gravels is that they’re pricier. There’s no doubt these gorgeous rocks will deliver on their promise to make your tank stand out. So, those of you who are on a budget will want to look elsewhere. However, these gravels are worth the investment for fishkeepers with more wiggle room in their budget.

PROS

  • Non-toxic coating
  • Safe for use in freshwater aquariums
  • Beautiful turquoise color

CONS

  • Pricier than other options
  • Some fishkeepers may not love the bright color

7. Abnaok Aquarium Stacked Stone Rock Decor

Abnaok Aquarium Stacked Stone Rock Decor
  • Manufacturer: Abnaok
  • Package Dimensions: 6.89 x 4.49 x 4.17 inches
  • Package Weight: 9.59 Ounces

The last rock on our list is the Abnaok Aquarium Stacked Stone Rock Decor. We love highlighting small businesses with a passion for fishkeeping, and Abnaok is definitely one of those businesses. These artificial rocks are thoughtfully designed to provide a touch of class to your tank, while providing hiding spots for your fish.

Artificial tank decor may not be everyone’s cup of tea, but these stacked rocks serve as a reminder that not all fake rocks are bad. In fact, sometimes artificial options can be better than natural ones. For example, these rocks are completely safe, inert, and non-toxic. They won’t change your water parameters or leach any harmful chemicals into your tank.

These rocks are also extremely lightweight and easy to move around. However, its lightweight construction also makes it a little more fragile than your average rock. So, these might not be the best choice if you have larger, more active fish. You’ll also need to be more careful when cleaning your tank, as you don’t want to accidentally break these rocks.

PROS

  • Safe, inert, and non-toxic
  • Lightweight and easy to move around

CONS

  • More fragile than the average rock
  • Not ideal for larger, more active fish

FAQ

Can You Clean Aquarium Rocks With Vinegar?

Vinegar is often used to clean aquarium rocks because they are non-toxic and won’t harm your fish. They are especially useful when dealing with stubborn algae or hard mineral deposits that may have formed on your rocks.

To clean your rocks with vinegar, simply fill a container with one part vinegar and one part water. Then, let your rocks sit in the mixture for at least 24 hours. This will give the vinegar time to break down any algae or mineral deposits that may be present. Then, simply remove your rocks from the vinegar and rinse them thoroughly with clean water.

*Note: Remember not to clean carbonate rocks, such as limestone, with vinegar! Vinegar is acidic and will react with these base rocks to form carbon dioxide and water.

Should I Boil Rocks Before Placing Them Into Aquariums?

boiling water

Yes! Always boil your rocks, gravel, and substrate before adding them to your aquarium. This will kill any bacteria, parasites, or other harmful organisms that may be present. If your rocks are coated with paint, glues, or other chemicals, boiling them will also help to remove these contaminants.

Can You Use Live Rock In Freshwater Aquariums?

Live rocks typically refer to rocks taken from the ocean and placed into aquariums. These rocks are often home to various marine life, such as algae, microorganisms, and small invertebrates.

While adding these rocks to freshwater aquariums is technically possible, it’s important to note that the “life” present on these rocks is adapted to saltwater conditions. This means that placing them in a freshwater aquarium will almost certainly kill the organisms present.

Therefore, we recommend against using live rocks in freshwater aquariums.

The Takeaway

Whether you’re among the hoards of seasoned aquarists who have been keeping fish for years or a complete novice just getting started, we hope this guide has given you some helpful insight into some of the best rocks you can use in your freshwater aquarium. Rocks aren’t just helpful in creating a natural habitat – they also improve the general well-being of your tank.

So, don’t be afraid to experiment with different types and sizes of rocks until you find the perfect fit for your aquarium. And, as always, happy fishkeeping!

Wanda is a second-generation aquarist from the sunny tropics of Malaysia. She has been helping her father with his freshwater tanks since she was a toddler, and has fallen in love with the hobby ever since. A perpetual nomad, Wanda does her best to integrate fish-keeping with her lifestyle, and has taken care of fish in three different continents. She loves how it provides a nice break from the hustle and bustle of life.

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.