Most fish tanks have something on the bottom — often gravel in freshwater tanks, but sometimes sand or other materials. What substrate is best for your tank?
Colored gravel is popular among casual fish keepers, but not often seen in a serious hobbyist’s tank. Why?
- If the fish should be the main focus of the tank, brightly colored gravel can be distracting from the living creatures.
- Colored gravel doesn’t look at all natural, and many serious hobbyists want their tanks to look like a little piece of nature.
- Light colored gravel can make fish nervous or anxious — the fish may feel like they are unable to hide. Many fish are dark-colored on top to blend in with the ground and be less visible to predators above. If your gravel is too light, your fish lose their natural camouflage!
Natural gravel is an option that will keep your fish more comfortable. Most natural gravel comes in a mixture of black, tan, and brown — these darker colors will help your fish think they’re blending in.
Other benefits of natural gravel include:
- The colors will complement other tank features, like driftwood and plants, without overshadowing them.
- Natural gravel is generally rounded — not sharp — so it won’t be dangerous to bottom dwellers.
- Natural gravel comes in a variety of sizes (diameters) so you can choose the best one for your tank situation. Larger sized gravel works well with under-gravel filtration, because it allows better water flow. Smaller sized gravel keeps waste and uneaten food from sinking too deep.
Sand alone can be a problem for your freshwater fish tank. Strong water currents can stir up the sand; the sand may carry pollutants that can be dangerous to your tank residents. However, sand can be a good choice for your saltwater tank — especially “live” sand. Live sand contains tiny organisms that provide food for tank dwellers.