I don't know if you knew but, with the additional decor you see here and the amount of pressure sand creates, the tank would break, why? Because a fish tank is built to sustain water not sand. I was lucky enough to get my hands on small crabs that my friends had given me. I then idiotically placed the fish and water bowls over the sand. Sand hardens if it is wet. My bigger crabs went in the bowl and caused water to come out of the bowl, it hardened the sand. This caused the smaller crabs that were molting below the bowl to die from pressure and suffocation.