Aquarium Hardscaping

Reviewed by Don Spaeth

Intro to Aquarium Hardscaping | Function of Hardscaping | Popular Substrate Choices | Popular Rock Choices | Popular Driftwood Choices | How to Create Aquarium Hardscape

aquarium hardscape live animals, rock, and wood

Whether you care for a solo betta in a five-gallon aquarium or a variety of aquatic life in a big community tank, your aquarium hardscape not only provides visual appeal but is essential for fish health and wellness.  

Introduction to aquarium hardscaping

Your aquarium hardscape includes items like driftwood, aquarium hardscape rocks, coral, caves and substrate. 

The second part of your aquascape is known as the softscape, which includes your aquatic plants. You also have functional accessories like your filter, lights, oxygenation, heater, etc. Here we will focus on just the hardscape of your aquarium.

What is the function of aquarium hardscaping?

Your aquarium’s hardscape is the foundation of the entire habitat. It helps influence the health and happiness of all your aquatic life. Hardscaping can also add beneficial tannins and surface area for healthy bacteria to colonize in your pets’ ecosystem. 

Aquarium hardscape rocks and driftwood provide places for your aquatic life to hide. Driftwood also provides a food source for algae eaters. Your substrate provides feeding grounds for catfish and algae eaters and can affect or help you maintain healthy water quality. Substrate also provides a foundation for any live plants you add to your softscape to grow and flourish. 

Most popular substrate choices

The aquarium sand, gravel or substrate you choose for your aqua hardscape depends on the type of aquatic life, the look you want and whether you have live plants. 

aquarium substrate

Sand

This is the finest type of substrate and a popular choice by some aquarists for a natural-looking hardscape aquarium. Sand can be a good choice for burrowing fish—including catfish, loaches and wrasses—and is often used in saltwater habitats. Sand grains come in various sizes—from .25 to 3 or more millimeters in diameter. 

Gravel

Gravel is a great choice for freshwater aquariums because it allows water to flow through it, helping to prevent the buildup of detritus. Gravel is heavier and larger in diameter than sand—at about 3 to 6 millimeters. It also typically comes in more diverse colors than sand—such as black and neon—so it may better match your desired look. You don’t even have to choose one over the other—one fun aquarium hardscape idea is to use sand and gravel for an interesting textured effect. 

Nutrient-rich substrate

Clay, basaltic, stratum and peat-type aquarium soils are commonly used in planted aquarium hardscapes. Substrates between  1 to 3 millimeters in diameter are typically utilized. This helps prevent compaction by allowing water and oxygen to flow to your plants’ roots. It can also improve or change your water’s pH level—so it may take some tinkering to find the right balance for your habitat. 

The nutrients in aquarium soils will deplete over time, which means you’ll periodically need to replace it or add more. You can also use organic potting soil that has been cleaned and filtered, but this is not recommended for beginning plant aquarists.   

Most popular rock choices 

The type of aquarium rocks you choose depends on your aesthetic as well as the size of your fish and your aquarium. 

aquarium rock hardscaping

Natural rocks

Natural aquarium hardscape rocks are very popular. They look great, come in various shapes, textures and colors and are low-maintenance. Some popular natural stones include:

  • Seiryu is a blue-gray, jagged stone that looks like small granite mountains. It does release carbonates when submerged, which can increase your water hardness and pH. 
  • Dragon Stone, also called Ohko, is a light, porous rock with an interesting textured look—you can even attach plants to it. Better yet, it won’t affect your water hardness. 
  • Elephant Skin is naturally found in caves, where it’s been shaped by magnesium-rich water that gives it a shiny, textured and variegated look. This type of rock can raise water hardness and pH.  
  • Pagoda Stone is a unique layered rock that comes in many colors—including red, black and brown—but can also raise water hardness and pH. 

You can also collect your own rocks for your aquarium, but stick to granite, lava, slate, sandstone, onyx or quartz. Stay away from calcites, marble, geodes and alabaster, and don’t use rocks that crumble easily, have sharp edges or come from polluted areas. Be sure to clean all rocks thoroughly before you hardscape your aquarium. 

Most popular wood choices 

Natural woods native to aquatic environments can also make visually appealing additions to the hardscape in an aquarium and provide benefits to your plants and pets. 

aquarium hardscaping driftwood

Natural driftwood

Driftwood in your aquarium can help you create a variety of fascinating looks that are sure to be conversation starters.  

Driftwood can be very good for aquariums when used properly. It naturally releases tannins into the water, which can help boost natural immune systems in aquatic life to lower your pH and is especially helpful if your water is alkaline. You’ll likely see these  effects within the first few weeks, but you’ll need a long-term solution if your pH remains high. Tannins can also increase the amount of oxygen in the water.  

Aquarium wood can also promote the growth of beneficial bacteria, helping to balance the ecosystem. Beneficial bacteria love to grow on the added surface area of driftwood, and these colonies can help break down waste. It isn’t just bacteria that benefits from driftwood—aquatic life love it, too. It likely exists in their natural habitat in some form, providing them with a place to hide, breed and explore. And for algae eaters, it can provide an excellent food source.  

  • Bogwood has unique color patterns and comes in jet black, dark brown and red-brown colors. Real bogwood can be difficult to find—today, most woods are dried outside rather than undergoing the long process of anaerobic preservation.
  • Burma petrified wood stone is gaining popularity thanks to its beautiful texture, variegated color and variety of sizes. 
  • Malaysian driftwood is a traditional standby—it’s rugged-looking, comes in many sizes and shapes and breaks down slowly. Like mopani wood, it’s very dense and typically won’t float when you add it to your aquarium. It has natural, rugged good looks and is extremely versatile. Moss and live plants take well to it.
  • Spider wood is actually a root—and as its name implies, it does resemble a spider. Because it is a root, spider wood is very light and will need to soak for a long time before it sinks. Spider wood also does not leach as many tannins as other species of driftwood.
  • Cholla wood comes from cacti and has a porous, hollow texture that many smaller fish and algae eaters love.

Can you find your own driftwood? Yes, but be sure to properly clean, sterilize and soak it. Also, be sure to only use hardwoods—softwoods can deteriorate quickly and leach into the water. 

 

How do I prepare driftwood for an aquarium?

 

Whether you get your aquarium wood from a store or your local pond, river or lake, you must properly clean, sterilize and soak it before adding it to your habitat. Here’s how.  

Clean:

First, use a clean, dry brush to wipe off dirt or dust. Then add clean, plain water and scrub the wood to remove anything else on it. Always use a brush that has never been used before—an unused toothbrush should work well—and ensure your water and the bucket you put it in are also clean and free of any cleaning solutions or soap.  

Sterilize:

You can sterilize driftwood by boiling it in water. The length of time depends on the size of the piece and the type of wood but can range from 30 minutes for smaller, softer woods to several hours for large, hard pieces of wood. If you need to boil the wood for a long time, add water as it evaporates to keep the entire portion of wood submerged.  

Boiling is the recommended way to sterilize driftwood, but what if you have a very large piece that won’t fit in a stovetop pot? You can also soak it in a solution of 2–3 tablespoons of bleach per gallon of water for about 24–48 hours. Make sure your bleach solution isn’t too strong, and after soaking your driftwood, place it in another bucket of clean water and a dechlorinator for around a day to get rid of the bleach before you add it to your aquarium.  

Curing:

Curing is the process of removing some of the tannins from your driftwood and weighing it down. You don’t necessarily have to cure driftwood for aquariums, but it has several benefits. First, it will help your driftwood sink to the bottom rather than float on the top, which is especially important for lighter woods like cholla wood and spider wood. Second, allowing some pre-leaching  of the tannins can help keep your water clearer. Without leaching, most driftwood can cause the water to become yellow or brown. This is fine for aquatic life (and even beneficial), but most aquatic parents prefer clear water and clear views. 

To cure your aquarium wood, all you have to do is soak it in plain, clean water. Choose a container that can completely submerge the wood, and change the water every day. How long will it take? That depends on the size and type of wood, but typically about 1–2 weeks. Continue changing the water daily until it is clear and you’re ready to add it to your aquarium.  

How to create an aquarium hardscape

Now you’re ready for the fun part—building your aqua hardscape. Here’s what you need to know to create a unique and thriving aquarium environment:

Plan your layout

Choose the types of rocks, woods and substrate that work for your aquatic life, your aquarium size and your desired aesthetic. Map out where you’ll put them in your enclosure, taking into account where your aquatic life might like to hide, feed and interact.

Prepare rocks and wood

How best to prepare your hardscape aquarium will vary depending on your chosen materials. Natural stones should be soaked in hot water, rinsed and scrubbed with a firm brush. Found rocks should then be soaked in a diluted bleach solution—2 to 3 tablespoons of bleach per gallon of water—for 48 hours, rinsed, soaked again in clean water with a dechlorinator additive and dried thoroughly. For help during this step, check out our guide How to Dechlorinate Tap Water. 

Whether found or bought, driftwood should be thoroughly scrubbed and sterilized by boiling or the bleaching method outlined above.  

Prepare and add substrate

You’ll also need to clean your substrate—even if it comes from a store, it can still contain dust. Add your gravel or sand to a bucket, fill it with water and use your hand to move it around to rinse it. Leave the hose or faucet running over the substrate for about 15 minutes to ensure it is thoroughly rinsed.

Now you’re ready to add it to your aquarium. You can just pour it in if you’re only using one type. However, you may want to add layers of different substrates or create patterns of different colors.  

Add rocks and wood

Now that your aquarium hardscape’s rocks and wood are clean and sterile, you can add them directly to your habitat. If you have a larger aquarium, you’ll want to add rocks first so that you can stack them and ensure they are stable before adding your wood. You can use aquarium silicone to glue them together so your aquatic life can’t knock them over. Also, make sure your rocks aren’t touching the glass, as it could cause a crack. Next, add your driftwood, making sure it’s secured to the bottom of the habitat by embedding it in the substrate or attaching it to a rock. Once all the elements are secure and in place, your hardscape is complete. 

Shop Aquarium Substrate

Shop Aquarium Rocks

Shop Aquarium Drift Wood

Reviewed by: Don Spaeth

Don is Petco’s National Aquatic Care, Education and Programs Manager. He is an avid aquarist who has worked with and cared for freshwater and marine aquatic life for over 40 years. Throughout his 27+ years with Petco, Don has actively been involved with our aquatic vendor partners and worked to promote aquatic education both in store and company-wide.

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