The
first consideration when decorating an aquarium, or aquarium aquascaping, is
the gravel. The
size of the individual pieces of gravel is particularly important if the tank has
an undergravel filter. If the gravel is too large, there won't be as much total
surface area for the nitrifying bacteria. On the other hand, if the gravel is
too small, it will clog with particles easily and restrict the flow of water
through the gravel bed.
The
best gravel sizes are #2 or #3, which are two and three millimeters in diameter
respectively. Although the color of gravel is a matter of personal choice,
neutral colors are more natural and do not compete with the fish for attention.
They also help to make the fish more comfortable.
You
may notice that many fish are dark on top and lighter on the bottom. This is a
form of camouflage called counter-shading. The fish will be less visible to
predators when viewed from above against the dark bottom of a stream or pond,
or when viewed from below against the light color of the sky. For this reason,
fish feel more secure over dark gravel.
