My black goldfish has just developed little hole where his fin is attached to the body, it pretty much goes all the way across the fin:( It has only appeared within the past week.
Currently I do 100% water changes every week, although the past few weeks have gone a little over the 7 days so I assume the ammonia has built up. Anyways I did a 100% water changes last night, added some esha 2000 and today I did a 50% water change and added more esha2000. However he seems worse today in himself... He is just sitting at the bottom of the tank and not really attempting to even swim:( Is there more I can do for him? Oh and he is an only goldfish and is in a tank around 70/80 litres.
I had this problem a few years ago with a fish and through all my attempts his fin rot got a million time worse and he died:( So I really want to avoid it this time.