Thanks everyone!
For the most part, Sushi and Ember look very happy. I am doing ~30-50% water changes every 3 days or so, but Ember's tail kind of looks like it might be getting worse.. or just might be becoming more pronounced as it heals.. it's hard for me to tell. He is, however, gaining a blue sheen throughout his body, which is new! I can only assume that's a good thing... please advise?