Selecting Aquarium Substrate

Goldfish with pink gravel substrate

Best Aquarium Substrate Guide

The material found at the bottom of your aquarium is known as substrate. Choices for color and style are numerous, offering every aquarist the experience of personalizing their tank. Aquarium substrate sizes range from fine grains of sand to large stones. These can readily be chosen to create a natural, homely habitat for your fish that suit their individual feeding and traveling needs.

Water parameters may be met by using substrates that buffer pH and carbonate hardness in your water so that your fish feel comfortable and are less likely to catch disease. Immense biological filtration is provided by substrate because bacteria thrives on the surface area that is covered with settled debris and therefore nutrients. The best choices of aquarium substrates are as follows:

Crushed Coral Substrate

Crushed Coral is a beautiful substrate that creates the appearance of an ocean floor. Since its colors are white and grayscale, this substrate will make your fish and coral colors stand out vividly. Containing calcium carbonate, it will help buffer the pH and hardness of your water; perfect for marine ecosystems which desire a slightly higher base pH and hardness. Crushed coral has a large surface area, making for a healthy bacteria home. However, since it has such large gaps, crushed coral catches much debris. The debris decays and the substrate turns into a nitrate factory which harms your ecosystem greatly. Being heavier and larger, invertebrates such as snails will not be able to effectively move in it to clean. Your decision to utilize crushed coral depends on your aquarium household. Plants may live with crushed coral if a bottom, soft and vitamin-rich aquarium substrate is provided. Your fish species must not have delicate fins, habits of burrowing or sleeping in sand. Ultimately, your tank household is adaptable, the decision ultimatum is whether you are willing to manual clean the substrate with a gravel-vac device to keep nitrates from building up.

Carib Sea Crushed Coral
Crushed Coral substrate
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Aquarium Gravel

Aquarium gravel is composed of small pieces of non-calcareous stones such as granite and basalt. Gravel is the most popular form of aquarium substrate in freshwater tanks largely because these rock choices do not affect water chemistry. This makes for a near neutral pH and softer water. Most freshwater fish prefer soft water and a neutral pH because they mimic natural habitat.Gravel is desirable for children as it is makes tank maintinence easy, colorful, and fun by:

Before deciding upon gravel as your tank substrate, consider the delicacy of your beloved fish. Gravel can be jagged and is not for burrowing and digging. Some species of fish can be harmed or deprived of natural habits when living with gravel. For example: Cory Catfish have fragile whiskers that get damaged by being bashed against gravel.

Learn more about gravel choices here

Sand As Aquarium Substrate

Create smiles on the faces of your fish by turning their aquarium into the ultimate vacation destination. Sand is natural, beautifully textured and colored, and luxuriously soft for your fish. White sand for aquarium flooring appears fresh and allows decorations in your tank to pop out. Colored sand adds unique style to conservative decoration or a finish to a bright aquarium. Most fish prefer sand as their substrate because it is easy to move through and is delicate on their fins. It makes for a great sleeping bag and playground for your jubilant fish to play and roll in the sand like children. Consequent of sand creating a homely feel for your tank, fish are increasingly likely to spawn because they are optimally comfortable.
Though sand is a wonderful and typically harmless substance, maintain caution when establising it in your tank:

is available in multitudes of colors and types. Sand types include coral sand, aragonite sand, tahitan moon sand, silica sand, "black beauty" sand, and live sand.

Learn more about various types of sand here

To add structural decor to your aquarium, as well as helping to maintain a stable pH and water hardness or softness, consider:

Aquarium Rocks

Introducing rock structures to your aquarium is visually appealing, comforting for your fish, and reacts with your water chemistry to replicate natural habitat water.

Rocks add:

Types of rock recommended for freshwater aquariums include slate, shale, and dried rock. For marine tanks, any of the above can be used as well as live rock. The reason live rock is not recommended for freshwater tanks is because they contain salt and marine bacteria that are harmful to freshwater habitats.

Learn more about rocks for your aquarium here.

Aquarium Wood

Wood in your aquarium makes for a great replica freshwater habitat of lakes and rivers. Common wood types used in aquariums are bogwood, mopani wood, malaysian driftwood and any other safe, petrified wood from pet stores. Wood pieces make hiding places for your fish so that they can have privacy and a comfortable spawning space. Algae and any micro-organisms will tend to live near or on the wood, and create a nutritious food source for your tank mates. Wood will decrease your tank water pH and soften the water. These parameters are favorable for freshwater fish because it nearly replicates fresh water bodies of water; their natural habitat. Points of consideration for your driftwood to ensure safety in steps are:


To promote plant growth in your tank, add a layer of one of these great nutritious substances underneath your top layer of aquarium substrate:

Aquarium Plants

What Substrate to Use In a Planted Tank?

Aquarium plants are highly beneficial to your tank because they eat toxic nitrates which bacteria cannot eat, compete with algae for nutrients so that you do not get algae infestation, and give scenery, interaction, and oxygen for your fish. Being plants, they need essential nutrients such as iron, magnesium, potassium, and nitrogen to thrive. Without these, they will not reach their potential in color, growth, strength, and overall health. Take these measures to help your aquarium plants get, and stay healthy and blooming:

Seachem FlouriteCarib Sea Eco-Complete
Flourite substrate Eco-complete substrate
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View on Amazon

Aquarium Substrate Depth

Building your substrate layer to be four inches or lower in height enforces safety, comfort, and aesthetic appeal. While it may seem inviting to envision an aquascape featuring rolling hills of sand, it is not recommended to allow your sand height to be above four inches because:

Note: Do not keep deeply rooted plants in a tank with high sand levels. Growing roots may pop nitrogenous bubbles and release toxic gases into your tank. Great prevention can be sought by the addition of Malaysian Trumpet snails to your tank. They sift through and clean very deep sand beds, along with constantly disturbing substrate to prevent nitrogenous bubbles. Another option to keep your substrate disturbed is to manually stir the tank each week with your hand or any device.

Bare Bottom Aquarium

>Bare bottom aquariums are used for fish breeding, fry raising, quarantine tanks, and temporary-housing display tanks in pet stores. Bare bottom tanks are sometimes used to make catching fish easier in temporary tanks. Maintaining a bare floor is easy as debris does not get trapped. For small tanks with inadequate filtration and no intertebrates to clean debris off your aquarium substrate this may be beneficial. A buildup of decomposing debris may cause algae bloom and increased ammonia, nitrite and nitrate levels, resulting in fish illness.

This also means that no healthy bacteria will grow on the bottom of your tank. Substrate serves as a huge, natural surface area for bacteria colonies which eat ammonia and nitrates. Light can bounce off the bottom of your tank and stress our your fish, potentially causing agressiveness and vulnerability to disease. Deciding whether a bare bottom tank is right for you depends on the inhabitants of your aquarium. No substrate bottoms are not recommended for tanks with plants and certain fish because:

Cleaning Aquarium Substrate

Keeping your tank clean is a fundemental of the aquarium hobby. Without a clean tank, water parameters spike out of control, fish catch diseases, plants droop, and tank appearance turns dirty. Aquarium substrate largely impacts the cleanliness of your aquarium because the debris that settles on it is the same debris that decomposes into excess nutrients and harms your tank water parameters. Luckily, cleaning your aquarium substrate is easy with the use of our filters, gravel-vacs, and turkey basters. Simple advice for substrate cleaning is as follows: