I have a question regarding what to do with my tank sice my Betta fish died 2 weeks ago. It is a 5 gal tank, and I believe he died from a bacterial infection. He did not have ich, or dropsy, velvet or any other outward disease. He just stopped eating and would stay at the bottom of the tank gasping for air. I treated the tank with aquarium salt and Melafix, but It was too late. My son now wants a new Betta, but I want to make sure that the tank is clear of any disease. I haven't treated the tank since the fish died or changed the water. What would be the best way to make sure that the tank is ok for the next fish. I have heard about using bleach in the tank, but I'm not sure if I need to go that extreme. Any help would be appreciated.