I’ve had this goldfish for 6 years. In a 20g cycled tank. 0 ammonia. I do 25% water changes at least once weekly, sometimes more than that. Recently added aquarium salt, he was bottom sitting and water changes weren’t helping. that problem has resolved Today I noticed he was missing about 5 scales in one spot! Since it’s only in the one spot I assume he hurt it rubbing up against something. I haven’t added any new decorations to the tank, should I remove something? What can I do to encourage healing besides water changes? This happened today, I check on him all the time and he was fine last night. Included a pic of missing scales and current tank set up. How long does it normally take for scales to grow back?