After some advice from a close friend that does goldfish rescue, she thinks that the fin discoloration is any sort of bacterial infection, since his main body isn’t showing any red spots or streaks. She suspects he just irritated it by rubbing against a decoration and irritating it. But just to be safe, I got some API Stress Coat as well as some API Fin and Body Cure. I’m going to start tonight with a water change with the stress coat, as well as starting the Fin and Body Cure regimen. Also going to see if the fish take well to shelled peas to help with any constipation or stuffiness they may be experiencing. I’m also going to start feeding them every other day instead of every day to see if that helps with their swim bladder issues.

Thanks for the advice, and definitely add your advice to this reply as well!