Ya ok u win also I'm want to upgrade but it's hard since I'm not an adult and my parents limit everything check out my other thread plz because they want to move my arowana to a 125 which is still too smallI dont think someone who keeps a silver in a 55g really has the authority to diagnose anything.
To the OP, its definitely the start of fin rot. I would up the water changes and start a melafix and salt dosing.