im looking to set up a 10 or 20 gallon qt tank. I'll probably go for a petsmart kit. The tank will be set up in my daughters room. I understand the tank needs to be as bare bones as possible, but I'd like for it to look decent to help keep my daughter interested. Can any type of substrate safely be used? Maybe some gravel of some sort? How about dry rock? Are there any small fish that I could keep permently in the qt? I also plan on a 10 gallon coral/invert qt. Can that have sand and rock?