If you’re looking to add visual interest and appeal to your aquarium, you may have looked at different 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 for some inhabitants.
One important aspect 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.
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The 10 Best Rocks for Freshwater Aquariums
1. Pisces USA Seiryu Aquarium Rock – Best Overall
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 packages of various sizes of rocks.
The rocks 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 is that they will contrast well with plants in the aquarium.
These are limestone-based rocks, and 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.
2. SunGrow Mineral Rocks – Best Value
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.
The package 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. They are natural shades of white and grey and while they have beautiful surface texture, the edges are rounded to prevent injury to fish.
Since the 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, but they should be used as a small addition to your tank. These should be replaced every 6 months to retain efficacy.
3. Nature’s Ocean Natural Coral Base Rock – Premium Choice
The premium choice for aquarium rocks for freshwater tanks is Nature’s Ocean Natural Coral Aquarium Base Rock. In one order, you’ll receive 40 pounds of rocks, which is usually 2–3 rocks that are 12–17 inches in length.
The rocks are made from pure aragonite, which is an ocean rock that develops from long-dead coral. It features high porosity, and 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. The 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. They should not be confused with live rock and do not come pre-seeded with beneficial bacteria.
4. Margo Garden Products Rocks
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. The 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 they’re not made specifically for aquariums, they may have more dust than other types of rocks, so they’ll require rinsing prior to use. Some of these rocks may be larger than the 3 inches advertised. The size and weight may cause them to break in transit.
5. Lifegard Aquatics 10G-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. 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.
6. Carib Sea ACS00370 South Sea Base Rock
The Carib Sea ACS00370 South Sea Base Rock is 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. The 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.
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 the tank’s pH, potentially significantly.
7. CNZ Decorative Ornamental River Pebbles Rocks
The CNZ Decorative Ornamental River Pebbles Rocks are a great option for color variety at a fair price. The 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 they are cost-effective, you may need multiple bags to function as substrate for most tanks.
8. Pisces 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.
They are made from natural quartz and minerals, and 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 the rocks have a less stratified appearance than others, so it may be difficult to get rocks that meet your expectation of appearance. They have rough edges, and some sharp edges may harm fish, especially scaleless fish.
9. Lifegard Aquatics 25G-Smoky Mountain Stone Rock
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 three small rocks, two to three medium rocks, or two medium rocks and one large rock. The rocks are 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.
10. MCombo Aquarium Gravel Mini Agate Stone
The MCombo Aquarium Gravel Mini Agate Stone is a colorful purchase for fish tanks. The packages contain 100 stones, but these stones are very small, so this is only 1–2 handfuls.
The 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 the 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.
Buyer’s Guide – Choosing the Best Rocks for Freshwater Aquariums
If you already have a vision for the appearance of your aquarium with the addition of rocks, these reviews should help you identify the rocks you want to use. 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 premium selection is the Nature’s Ocean Natural Coral Aquarium Base Rock, which is beautiful and functional but also premium-priced.
Choosing rocks shouldn’t be hard! There are tons of rocks out there, and purchasing rocks that not only look the way you want but are also 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 love the attractive appearance they provide.
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