Why use substrate in aquariums? 1. Good looking – Let’s be realistic. The main reason people use a substrate is because it enhances the look of the aquarium. 2. It’s natural – Do fish in the wild have a glass-bottomed habitat? No. By using a substrate, you are creating a more natural environment for your fish. 3. Enhances your fish – You can use the substrate to make your fish pop. Dark fish are easier to see on a light-colored substrate while light-colored fish are easier to see on a dark substrate. 4. It houses bacteria – You know those beneficial bacteria that take part in the nitrogen cycle? While the majority of them live in your filter, some also cover the substrate of your aquarium. In fact, you can use the substrate from an established tank to make your brand new aquarium cycle faster 5. Plants need it – Plant roots need to go somewhere. Without a substrate, your plants will float to the top of your tank. As you see, there are some pretty compelling reasons to use a substrate in your aquarium. Sand is considered the most natural substrate since most aquarium fish are from an environment that has sand, silt or mud – all of which sand accurately replicates. Sand also has little to no gaps between each grain, meaning nowhere for uneaten food and poop to get stuck – making sand one of the easiest substrates to keep clean.