So I check on my goldfish a couple days ago after I had been away for the day and found that he seemed to have some sort of injury on its pectoral fin. I was told on another goldfish group that it looked like a minor injury and treating with a peroxide swab should do the trick. Three days later and nothing has improved and in fact gotten worse. The blood seems to be pooling into the fin more and starting to come onto the body. My fear is that he broke his fin and, because he can still use it, is making it worse by swimming. When he rests the fin lays by his side kind of limp, but he does have movement with the fin. I'm not sure what to do at this point to help it heal. I've included some pictures in the links below.
Fin 3 days ago
Fin today