Fin Rot, time to call in the big guns

Hi, my black moor has had this twice. I got rid of it both times with
daily water changes and salt. I did use Furanase the first time with
the salt and water changes but couldn't get any the second time so I
just used the mentioned. Somebody did point out to me that it might be
'black molly's disease' due to too big a water change. Kept the
frequency up but cut back on the amount. He recovered in no time.

Hope this helps
Mellie