10 Best Rocks For Freshwater Aquariums | Safe Stones Guide

Typically, we wouldn’t recommend adding river rock to your tank. It can transmit bacteria that isn’t native to your ecosystem and cause a lot of damage to your fish.

However, aquarium river rock is some of the most beautiful stones you can add to your tank.

Royal Imports river pebbles are one of the few brands of river rocks we would recommend using. They not only help your tank appear more attractive, but they also help create a system that your fish and invertebrates can thrive inside.

The most common use for these river rocks is tying down plants and giving your tank hardbottom sections for fish that prefer them over sandy bottoms. The stones vary in size, shape, and color, which helps add a unique flair to your tank.

Each of the stones in the Royal Imports bag is rolled and tumbled, giving them a polished look that remains rugged. This process helps bring out the colors and luster, letting the undertones shine through when water hits them.

If you are looking for a natural appeal, these river rocks contain the most natural colors you will find. Browns, greys, blacks, and tans make up the entire range.

While these river rocks are cleaned and tumbled before arriving at your doorstep, you do still want to make sure you are cleaning them thoroughly to remove any small debris.

When you want to add visual appeal to your freshwater aquarium, the Pisces Seiryu rocks are a great way to do it. These are a hardscape rock that is humanmade to help provide a realistic look, feel, and weight.

If you are familiar with Amano or Iwagumi aquascaping, you understand the appeal.

Since these rocks are humanmade, you do not need to worry about them being toxic to your fish, plants, or other animals in the tank. The all-natural stones are great for shrimps and other plants and do not modify your water’s chemistry.

These rocks are widely regarded as some of the best rocks you can put in your aquarium.

They are a porous rock, so you don’t have to use toxic or harmful chemicals to help hold them together or keep them in place while you are stacking them. Compared to other rocks, these have been said to have an “out of this world” look.

The natural colors and large sizes can be broken down to expose the undertones and create smaller stones you can use as accents. It’s easy to create an island structure with these rocks.

One of the most significant selling points of Atlantic Coral Rocks is their price range. They are far cheaper than many other types we’ve seen. With aquascaping being such an expensive hobby, save money where you can!

While these rocks do look amazing in your tank and come alive underneath an LED light, they serve another beneficial purpose. Healthy bacteria can grow and thrive in the porous surface, and your fish will learn to feed on them in between your scheduled feeding times.

One of the coolest decorations you can add to your tank is natural slate stones.

They double down as both a decorative addition to your tank but also a great way to keep your plants firmly rooted. When your plants are close to the inflow of your pump, they tend to move around. Flat slate stones keep the roots firmly planted while the tops of your plants can flow.

These are a natural grey color and become darker in color as they spend time in the water. They do not leech calcium or throw off the pH levels in your tank, so you do not have to worry about affecting the health of your fish by adding them into your aquascape.

Each slate stone can be broken, shaped, and molded to fit exactly what you’re going for. You can use them to create hideouts for smaller fish or stack them to create a water feature that uses your pump’s inflow to create tranquil background noise.

VORCOOL is a brand name that has been around aquarists and aquascaping for years.

The VORCOOL Sea Rock Cave is an excellent addition to any tank. Known for producing only the highest-quality decorations, you don’t have to worry about introducing harmful toxins to your aquarium as you do with knockoff brands.

This cave is a great way to help your smaller species hide and tuck away while also helping promote healthy bacteria growth that those same smaller fish can feed on.

However, with the beauty of the rock cave comes a single caveat: the edges can be sharp.

The molding process has been known to leave a few rough edges here and there so you will want to sand them down before you install it into your aquarium. These sharp edges can hurt your fish.

You will also want to make sure you scrub the cave with dish detergent or another mild detergent to help remove some of the release agents that are used during the molding process.

While the release agent isn’t harmful, it does have a pungent odor that can be offputting to some people.

SevenSeaSupply is another well-known company in the aquascaping industry.

The SevenSeaSupply Ohko Dragon Stones are an incredibly unique addition to any tank, too.

These natural stones help provide a haven for your smaller fish, giving them a structure to huddle around and relieve stress. The design also makes them incredibly visually appealing.

The rocks have naturally occurring creaks, cracks, and crevices for your fish to hide in and around, and to help promote healthy bacteria growth.

It is worth noting that these are humanmade stones. While they are natural materials, you will need to take care and wash them before installing them into your tank. You don’t have to worry about harmful chemicals, but some customers have reported a film reaching the surface of the water after installing the Dragon Stones.

Finding high-quality lava rock that is safe to use in your aquarium can be hard to do. The American Fireglass company’s Black Lava Rocks are the exception to that rule.

Each rock is a naturally-occurring stone, nothing humanmade here. They are relatively low maintenance and have been proven to withstand the test of time in tanks around the world.

One of the most significant selling points is the dark, deep black color that helps offset the more natural colors in your tank. You can use the lava rocks to hold down plants or create caves and nests where your smaller species can hideout.

Finding good coral rocks to use in your freshwater tank is nearly impossible to do. Unless you have access to a live coral environment near you, these can be impossible to source.

Nature’s Ocean knows how much aquarists love using coral in their freshwater tanks and started sourcing base coral rocks for reselling. This is a larger rock, in the 12-inch size range, so you’ll want to keep that in mind before you purchase.

Each piece of coral can be broken down to create a very specific aquascape. The coral rocks do not introduce harmful chemicals to your water but do have the potential of leeching calcium. If you use them, you’ll want to keep an eye on your pH and hardness levels.

The naturally occurring holes and crevices allow healthy bacteria to grow and give your algae eaters plenty of places to pick apart.

Cichlid Rocks from Underwater Galleries are another unique stone you can add to your tank.

They provide large caves for your smaller species to hide in and for, as the name suggests, Cichlids to breed in. The darker caverns are also great for helping promote healthy bacteria growth that your algae eaters can feast on.

The eco-friendly design of these stones is what helps set them apart. They do not displace as much water as other stones, and each stone is hand-glazed. The construction helps maintain a natural appearance that you can’t help but pay attention to.

Each package comes with six large stones and four medium stones, all with varying styles. The smaller rocks feature 1-inch openings while the larger stones feature up to 2-inch openings.

While the larger stones do allow your smaller fish to move in and hide, the smaller rocks make it harder for fish to get in and out. That means you will need to pay attention to keeping them clean, in case of algae bloom breaks out.

Finally, we have Penn Plax Stones. These are another unique stone that offers plenty of hideouts for your smaller (and larger) fish, as well as the ability to stack the rocks to create customized aquascapes.

Each stone is crafted to look like a real piece of granite that has been molded and shaped by flowing water for generations. Larger stones feature a flat surface to help make stacking easier to do.

A ton of customers has reported that these stones do not hold algae-like many other porous stones do, because of the materials they are constructed from.