Types of Substrates for Your Aquarium

Generally, when choosing a substrate, a beginner is advised to pick the type best suited for a specific type of aquarium. Substrates provide not just a terrain for your tank, but it will also lessen the light reflected off the surface of the aquarium that might spook the fish. It also serves as a playground, colony, and breeding ground for your pets and other microscopic lifeforms.

Tips for Choosing Substrates

Keep these in mind when choosing the substrate for your aquarium.

  • Research its reactivity with water
  • Make sure it’s easy to clean and will work with your filtration system
  • Consider how it will affect the bottom-dwellers
  • Fish-only tanks should have at least 2 inches of substrate
  • Reef and marine tanks need at least 2 inches of substrate
  • Planted tanks need two layers of substrate, with the lower level as high as the roots

Types of Aquarium Substrates

  • Common Gravel. Do not use glass pebbles and painted gravel for your aquarium, because they can injure your fish. Instead, choose common gravel that contain quartz.

  • Calcium Carbonate. Also called dolomite gravel, this is used in saltwater tanks, but it has a tendency to trap debris and uneaten food. If it is regularly cleaned, however, calcium carbonate can maintain ideal water conditions in the tank.
  • Sand. Sea sand isn’t recommended for aquariums because they could contain impurities that will harm your fish and change the water condition. It’s also difficult to clean, unless you have an effective filtration system installed. If you need to install sand, pick sandblasting sand and play sand instead.
  • Aragonite. This is a type of calcium carbonate that is ideal for raising the pH level in a reef tank. Most hobbyists mix aragonite with crushed corals and live sand to achieve the ideal water conditions in a saltwater tank.
  • Vermiculate. This substrate is made up of iron, aluminum, and magnesium, which is ideal for planted aquariums, although it has to be mixed with common gravel and laterite to keep its appearance consistent.
  • Crushed Corals. Like aragonite, crushed corals are ideal for saltwater tanks to create ideal water conditions. It is usually mixed with calcite and dolomite to make it suitable for almost all types of aquariums.

  • Laterite. This is a type of clay that contains iron oxide, ideal for planted aquariums because it can hold and release nutrients slowly over time. This is usually placed at a lower layer under another substrate.
  • Marbles. Choose large flat marbles that are easier to clean than the round small ones. This is usually recommended for aquariums made for breeding fish because the eggs can be hidden from predators in between the marbles. Another substrate, marble chippings, can also serve as alternative to coral sand.
  • Miracle Mud. This is a new type of substrate that is often used in saltwater tanks as a sump or to inoculate sand beds.
  • No Substrate. Most saltwater tanks prefer a bare bottom reef because it is easier to maintain. However, a tank with no substrate can be stressful for some fish.