the Right Substrate for Your Fish Tank
It’s important to choose the right fish tank substrate since
it can have an impact on everything from the water’s chemistry and filtration to
the health of the aquarium’s inhabitants.
If you need to alter your tank’s water chemistry, selecting
the right kind of substrate
can help you do the job naturally instead of using chemicals. The right
substrate can create beneficial bacteria, release substances, absorb substances
or create certain conditions by reacting with other substances present in the
For example, you can buffer your aquarium’s pH by adding
crushed coral or coral sand, since they both have calcium carbonate to raise
the level of hardness of the carbonate. Crushed limestone, marble and shell
grit can also be used to increase the water’s hardness.
If your fish need soft water, consider adding peat. It’s a
natural way to help the water obtain the same water chemistry as that found in soft
Something as simple as the colour of your substrate can have
an impact on the behaviour of your fish. For example, dark substrates can
really set off the colour of your fish and encourage them to behave less
If you plan on breeding your fish, remember that some fish
will eat their own eggs or the eggs of other fish. Dropping a layer of marbles
can help since the eggs fall between the gaps, safe from the fish in the tank.
Also remember when selecting substrate that some
bottom-dwelling fish use substrate to hide. It’s important to choose fine grain
substrate to avoid injuring the fish.
If you plan on including plants in your tank, be sure to
select a substrate that will remain loose. If it becomes packed, the plant
roots may not be able to break through. Avoid sharp substrate or anything
chemically treated. Instead, choose a fish tank substrate like fine gravel and
spread it so that it’s at least 5 centimetres deep.
It’s not uncommon to choose two layers of substrate if you
want living plants in your fish tank. Under the gravel, try something richer to
help nourish your plants. Choose potting soil, peat, vermiculite or clay.
Gravel is by far the most popular choice for freshwater
tanks. You can find it in many colours and sizes, making it easy to match your
décor or bring out the colour in your fish. It’s important to use aquarium
gravel since it’s chemically inert.
Saltwater tanks benefit from substrate that originates from
the ocean and is high in calcium content. Consider coral or reef, shell-based
substrate, or aragonite. You can find them in a wide range of colours and in
fine or small grain with medium to course textures.
Choosing the right substrate for your fish tank is about
more than just good looks. You have to consider the type of fish that will be
living in the aquarium, whether it’s freshwater or saltwater, the impact your
preferred substrate will have on the water’s chemistry and fish behaviour. A
fish tank’s substrate can do double-duty as aesthetically-pleasing as possible and
is a good way to keep your fish healthy.