If you’re looking to add visual interest and appeal to your aquarium, then you may have looked at different types of aquarium ornaments, but one of the easiest ways to achieve newfound beauty in your tank is through the addition of rocks.

Even though it sounds like an overly simple solution, rocks can be used to add color and texture to your aquarium. They can also be used to create shelters and hides, making the tank feel safer to some inhabitants.

One important thing about adding rocks, though, is that some rocks can alter your water parameters due to the introduction of minerals into the water, so you need to know exactly what you’re putting into your aquarium.

Ideally, you should be acquiring rocks and gravel from trusted sources to avoid introducing parasites, bacteria, plants, and other undesirables into your tank. These reviews of the 10 best rocks for freshwater aquariums will help you find safe rocks to add to your tank.divider1- goldfish

A Quick Comparison of Our Favorites

Image Product Details
Best Overall
Winner
Pisces USA Seiryu Aquarium Rock Pisces USA Seiryu Aquarium Rock
  • 17-pound bag of rocks
  • Naturally occurring coloration
  • Can be used to build caves or add texture
  • Best Value
    Second place
    SunGrow Mineral Rocks SunGrow Mineral Rocks
  • Best value
  • Naturally occurring coloration
  • Rounded edges to prevent injury
  • Premium Choice
    Third place
    Nature's Ocean Natural Coral Aquarium Base Rock Nature's Ocean Natural Coral Aquarium Base Rock
  • 40 pounds per package
  • Texture is great for stacking
  • Naturally occurring coloration
  • Margo Garden Products Rocks Margo Garden Products Rocks
  • 30-pound package
  • Can be used to attach plants to
  • Rounded and have smooth surfaces
  • Lifegard Aquatics 10G-Dragon Rock Lifegard Aquatics 10G-Dragon Rock
  • Will not alter water pH
  • Naturally occurring coloration
  • Can be stacked and used to attach plants to
  • The 10 Best Rocks for Freshwater Aquariums- Reviews 2021

    1. Pisces USA Seiryu Aquarium Rock – Best Overall1Pisces USA Seiryu Aquarium Rock

     

    The Pisces USA Seiryu Aquarium Rock is the best overall pick for freshwater aquarium rocks because of the attractive and varied appearance of the stones. These stones come in a 17-pound package of various sizes of rocks.

    These rocks will come in shades of white, grey, and occasionally brown, with some rocks being solid-colored and others being a natural combination of colors. This is a natural product, so the number, size, and shape of the rocks you receive will vary with each bag. These rocks can be used to build caves or just add texture to your tank. A benefit of the natural coloration of these rocks is that they will contrast well with plants in the aquarium.

    These are limestone-based rocks, so there is a chance of them altering the pH of your tank. For fish like cichlids this may be a benefit to keeping the tank at the alkalinity they prefer, but for dwarf shrimp and acid-loving fish, these rocks may not be a good option.

    Pros
    • 17-pound bag of rocks
    • Naturally occurring coloration
    • Number, size, and shape of rocks is variable
    • Can be used to build caves or add texture
    • Light coloration will contrast well with plants
    • Good option for tanks with fish that prefer alkaline water
    Cons
    • Limestone-based rocks may raise pH

    2. SunGrow Mineral Rocks– Best Value2SunGrow Shrimps and Crayfish Mineral Rocks

     

    The best rocks for freshwater aquariums for the money are the SunGrow Mineral Rocks because of their great price and benefit to tanks. These rocks come in a 60-gram package, which is just over 2 ounces.

    This package of rocks comes with a few varieties of rocks, including calcium rocks to improve mineral availability in your tank. They will also release other trace elements into your tank, improving the appearance and health of your fish and invertebrates. By improving the health of the tank, these rocks will improve the odds of reproduction within your tank as well. These rocks are natural shades of white and grey and while they have beautiful surface texture, the edges are rounded to prevent injury to fish.

    Since these rocks will release trace elements into your tank, they may harden the water and raise the pH level. It’s not advisable to use these as a substrate in your tank and instead they should be used as a small addition to your tank. These should be replaced every 6 months to retain efficacy.

    Pros
    • Best value
    • Naturally occurring coloration
    • Number, size, and shape of rocks is variable but all will be small
    • Calcium rocks included in each package
    • Improve health, appearance, and reproduction
    • Rounded edges to prevent injury
    Cons
    • Trace elements may raise pH
    • Should be replaced every 6 months

    3. Nature’s Ocean Natural Coral Aquarium Base Rock – Premium Choice3Nature's Ocean Natural Coral Aquarium Base Rock

     

    The premium choice for aquarium rocks for freshwater tanks is the Nature’s Ocean Natural Coral Aquarium Base Rock. In an order, you’ll receive 40 pounds of rocks, which is usually 2-3 rocks that are 12-17 inches in length.

    These rocks are made from pure aragonite, which is an ocean rock that occurs from long-dead coral. It features high porosity, so it provides excellent surface area for beneficial bacteria colonization. Nature’s Ocean pre-soaks these rocks prior to sale to decrease the leaching of minerals into your aquarium. These rocks are a naturally occurring shade of white and their texture makes them great for stacking to build caves and add texture.

    Since these rocks are made from aragonite, which contains high levels of calcium, they may raise the pH of your aquarium. They are intended for saltwater tanks but can be used for freshwater tanks. These rocks should not be confused with live rock and do not come pre-seeded with beneficial bacteria.

    Pros
    • 40 pounds per package
    • Large rocks
    • Provide excellent surface area for beneficial bacteria colonization
    • Pre-soaked prior to sale to decrease mineral leaching
    • Naturally occurring coloration
    • Texture is great for stacking
    Cons
    • Premium price
    • Aragonite may raise tank pH
    • Will only receive 2-3 rocks per box

    4. Margo Garden Products Rocks4Margo Garden Products

     

    The Margo Garden Products Rocks are a great option for adding small river rocks to freshwater aquariums. These rocks are 1-3 inches long and come in a 30-pound package.

    These rocks are natural shades of light to dark grey and can be used in aquariums or ponds. They are larger than gravel, so there is less chance of fish like goldfish accidentally consuming them or getting rocks stuck in their mouth. Since these rocks are smaller than normal-sized river rocks, they will not allow for as much waste buildup underneath and between them. These rocks are rounded and have smooth surfaces, so they should not harm fish. They can be used to glue or tie down plants like Java ferns.

    Since these rocks are not made specifically for aquariums, they may have more dust than other types of rocks, so they’ll require good rinsing prior to use. Some of these rocks may be larger than the 3 inches advertised. The size and weight of these rocks may cause them to break in transit.

    Pros
    • 30-pound package
    • Naturally occurring coloration
    • Too large for most fish to fit into their mouth
    • Less waste buildup underneath and between them than regular-sized river rocks
    • Rounded and have smooth surfaces
    • Can be used to attach plants to
    Cons
    • May have more dust than aquarium-specific rocks
    • Some may be larger than advertised
    • Some rocks may break in transit

    5. Lifegard Aquatics 10G-Dragon Rock5Lifegard Aquatics 10G-Dragon Dragon Rock

     

    The Lifegard Aquatics 10G-Dragon Rock is one of the best rock options for achieving the look of coral without altering your water’s pH. This package is intended for a 10-gallon tank and equals approximately 15 pounds of rock.

    These rocks have the porosity of aragonite without adding calcium to the water, so they are a great option for adding surface area for beneficial bacteria. They are natural shades of grey, usually medium to dark, and have a textured surface, which makes them a good pick for attaching mosses and other plants to. They have small, naturally occurring “caves” that some fish and invertebrates will appreciate. They can be stacked or attached to each other to create underwater scenes.

    These rocks can break easily and often have clay attached to them, which may be difficult to fully remove without damaging the rocks. The number of nooks and crannies in these rocks also makes it difficult to fully remove clay and dirt before use.

    Pros
    • Approximately 15 pounds of rocks
    • Will not alter water pH
    • Provide excellent surface area for beneficial bacteria colonization
    • Naturally occurring coloration
    • Can be stacked and used to attach plants to
    Cons
    • Come with clay stuck to them
    • Easily broken and difficult to clean without damage
    • Clay usually cannot be fully removed prior to use

    6. Carib Sea ACS00370 South Sea Base Rock6Carib Sea ACS00370 South Sea Base Rock for Aquarium

     

    The Carib Sea ACS00370 South Sea Base Rock are an attractive, coral-like rock at a premium price. One package weighs 40 pounds.

    These rocks are made from calcium carbonate and are great for saltwater and high-alkalinity freshwater tanks. They are natural shades of white and have a coral-like appearance. These rocks are porous but sturdy, making them great for beneficial bacteria colonization but at little risk of breaking with cleaning and handling. They can be stacked and used to attach plants to.

    These rocks are manmade and need to be soaked prior to use to prevent the leaching of minerals and silicates. They may even need to be soaked for days or weeks to decrease this. This is not live rock and since it is made from calcium carbonate, it will raise tank pH, potentially significantly.

    Pros
    • 40 pounds of rocks
    • Natural-looking shades of white
    • Provide excellent surface area for beneficial bacteria colonization
    • Sturdy
    • Can be stacked or used to attach plants to
    Cons
    • Premium price
    • Need to be soaked well before use
    • Calcium carbonate will raise pH

    7. CNZ Decorative Ornamental River Pebbles Rocks7CNZ Decorative Ornamental River Pebbles Rocks

     

    The CNZ Decorative Ornamental River Pebbles Rocks are a great option for color variety at a fair price. These rocks come in a 5-pound package.

    These river pebbles are smaller than river rocks but larger than most gravel, measuring 0.5-0.8 inches each, making them safe for most fish. They are various shades of naturally occurring colors, including greys, blues, tans, and reds. They have smooth surfaces and edges, making them safe for most fish.

    Since these are not made specifically for aquariums, they require a significant amount of rinsing prior to use due to dust. They may crack or break in transit, creating rough edges. Even though these are cost-effective, you may need multiple bags to function as substrate for most tanks.

    Pros
    • 5 pounds of rocks per package
    • Smaller than river rocks but larger than gravel
    • Multiple naturally occurring colors
    • Smooth surfaces and edges
    • Will not raise pH
    Cons
    • May have more dust than aquarium-specific rocks
    • May crack or break in transit
    • Multiple bags needed for tanks over 5-10 gallons

    8. Pisces USA Strata Aquarium Rock8Pisces USA Strata Aquarium Rock

     

    The Pisces USA Strata Aquarium Rock is a stratified, natural-colored rock for a reasonable price. One package of these rocks weighs 13 pounds.

    These rocks are made from natural quartz and minerals, so they have a slightly glimmering appearance in the water. They have a stratified appearance and are naturally occurring shades of tan to reddish-brown. Since these are naturally occurring, each package will have different shapes, sizes, and colors. They are intended to be stacked and their rough texture makes them a good option for attaching plants.

    These rocks are easily broken and may break or even shatter in transit. They create a lot of dust and need to be rinsed well prior to use. Some of these rocks have a less stratified appearance than others, so it may be difficult to get rocks that meet your expectation of appearance. These rocks have rough edges, and some sharp edges may harm fish, especially scaleless fish.

    Pros
    • 17 pounds of rocks per package
    • Slightly glimmering and stratified appearance
    • Naturally occurring coloration
    • Different shapes, sizes, and colors in each package
    • Can be used for stacking or attaching plants to
    Cons
    • May break or shatter in transit
    • Need to be rinsed well before use
    • May not have as much of a stratified appearance as expected
    • Rough edges may harm some fish

    9. Lifegard Aquatics 25G-Smoky Mountain Stone Rock9Lifegard Aquatics 25G-Smoky Smoky Mountain Stone

     

    The Lifegard Aquatics 25G-Smoky Mountain Stone Rock is a kit with enough rocks for a 25-gallon tank. One package is approximately 37 pounds of rocks.

    This package of rocks will usually include 3 small rocks, 2-3 medium rocks, or 2 medium rocks and 1 large rocks. These rocks are natural appearing shades of grey and tan. They are textured and can be used for stacking or building caves.

    It’s not uncommon to receive too few rocks in these packages, but they are usually within 1-2 pounds of 37 pounds. These rocks are easily broken, especially in transit. Sometimes, these rocks will be glued together to create larger rocks. These do need to be rinsed or soaked well before use.

    Pros
    • Approximately 37 pounds of rocks
    • Multiple sizes and shapes of rocks
    • Naturally occurring coloration
    • Can be used for stacking or cave building
    Cons
    • May receive too few rocks
    • Easily broken in transit
    • Sometimes these rocks are glued together to create larger rocks
    • Need to be rinsed or soaked well before use

    10. MCombo Aquarium Gravel Mini Agate Stone10MCombo Aquarium Gravel Gem Polished Natural Agate

     

    The MCombo Aquarium Gravel Mini Agate Stone is a colorful purchase for fish tanks. These packages contain 100 stones, but these stones are very small, so this is only 1-2 handfuls.

    These stones are brightly colored, polished agate stones that measure 0.3-0.7 inches each. They are in multiple solid and combination colors, including reds, pinks, purples, greens, yellows, and oranges. These are too large for most fish to fit into their mouths, but larger goldfish and cichlids may still get them into their mouths.

    Since these stones are so small, you will need multiple packages to create a substrate in most aquariums. These stones need to be rinsed and possibly soaked thoroughly before use to remove some of the waxy coating applied when they are polished. These stones may chip or break during transit, leaving rough edges.

    Pros
    • 100 stones per package
    • Brightly colored
    • Too large for most fish to fit into their mouths
    Cons
    • Only 1-2 handfuls per package
    • Multiple packages needed to create a tank substrate
    • Need to be rinsed and/or soaked well before use
    • Waxy coating is applied to these stones during polishing
    • May break during transit

    Buyer’s Guide

    What to Consider When Choosing Rocks for Your Freshwater Aquarium:
    • Appearance: What do you want your tank to look like with the addition of rocks? If you want to build caves or create aquascapes, then you may want textured rocks that can be attached to each other or have plants attached to them. If you want something that can function as a substrate in your aquarium, then finding smaller rocks, like pebbles and gravels, might be more of what you are looking for.
    • Animals: Some freshwater fish, like cichlids, will appreciate an alkaline environment, so they will do well with the addition of calcium-based rocks like aragonite and limestone. Other fish, like most tetras, will appreciate a slightly acidic environment, so it’s ideal to add rocks that will not alter the pH of your tank and use things like driftwood and Indian almond leaves to keep your pH low.
    • Plants: Like aquatic animals, some plants will not do well in a highly alkaline or acidic environment. Most plants prefer a slightly acidic to neutral environment, but primitive plants, like mosses, can thrive in alkaline environments.
    • Source: Knowing the source of your aquarium rocks is one of the most important aspects of choosing rocks. Some people collect rocks from local waterways, which can cause problems in your aquarium if you don’t clean the rocks well or identify them appropriately. Sourcing rocks from manufacturers that specify the rocks are safe for aquarium use is the best way to go when it comes to aquarium rocks. If you do decide to source rocks from local waterways or from private individuals, make sure you know how to identify the rocks and clean them thoroughly and safely before use.
    Use Caution With:
    • Minerals: The addition of minerals to aquariums will raise the pH of the water, leading to an alkaline environment. Most freshwater fish and shrimp prefer acidic or neutral pH environments, so use caution when adding any type of rocks that contain high levels of minerals, like limestone.
    • Coral/Aragonite: Aragonite is long-dead coral while coral rock is recently dead coral. Either way, both of these types of rocks contain high levels of calcium and can leach minerals into the water. Calcium is necessary for many invertebrates in some levels but use caution with the addition of these types of rock because they can raise the level of dissolved calcium in the water to levels that may create an unsafe environment for many animals and even some plants.
    • Polishes: While most rock and stone polishes are not going to alter water parameters in any significant way, some of them may be toxic or may become toxic over time. It’s good practice to clean any rocks before adding them to your tank, but polished rocks may require extra cleaning, scrubbing, or soaking to avoid introducing dangerous chemicals into your tank.
    • Rough Edges: Some fish will hurt themselves on sharp and rough edges! Be careful when adding any type of rough rocks to your tank, especially if you keep fish like fancy goldfish and bettas, who may tear their fins on sharp edges easily, or scaleless fish like eels, Corydoras, blennies, and knifefish.

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    Conclusion

    If you already have a vision for the appearance of your aquarium with the addition of rocks, these reviews should help you identify what type of rock you want to use. If you still aren’t sure what you want, use these reviews to help you narrow your search based on what you think you’ll want for your aquarium.

    The best overall rocks for freshwater aquariums are the Pisces USA Seiryu Aquarium Rock because they’re high-quality rocks that can be used for multiple purposes. The best value rocks are the SunGrow Mineral Rocks, which can also improve the health of your fish and invertebrates. The most premium rocks are the Nature’s Ocean Natural Coral Aquarium Base Rock, which are beautiful and function but also premium-priced.

    Choosing rocks shouldn’t be hard! There are tons of types of rocks out there, so knowing if what you’re purchasing not only looks the way you want, but also is safe for your tank is very important. Your fish and invertebrates will appreciate the shelter and comfort provided by the addition of rocks to their environment, and you’ll appreciate the attractive appearance they provide.


    Featured Image Credit: Green Yoshi, Wikimedia Commons