Hello! Sadly, my Betta Fish named Crimson passed away on Wednesday, which left me with an empty fish tank (5 gal.) since then. So I have a question, if I want to keep the tank up to get another Betta Fish, What should I do to the tank before doing anything? And to make my statement more clear I mostly mean what to do with things like the filter media, the water, the gravel, etc... Thanks!