so my fish have been showing signs of fin rot for a few weeks now. I at first though water changes would be enough but sadly they aren’t. I do not have the money for medicine however I did hear you can treat with hydrogen peroxide. I have a few questions such as how much? Is it safe for tetras? Do I need to remove my media? Will it crash my cycle? How long should I do it for? And how often? Any help is appreciated.