Last weekend one of my goldfish looked like it was about to pass away. It had lost a lot of scales on both of it's sides. It is also missing chunks of various fins but I think that is due to it moving so slowly and the turtles probably chewing on it. This happened happened in the time span of a day and the fish spent the night hanging out at the bottom of the pond. I added some Melafix to the water, the fish survived and is now moving around great and eating. However, in the spots where the scale loss occurred there is not what looks to be black almost moldy looking fuzz on the fish. Any idea of what happened to the fish and should I be concerned for the rest of the wildlife in the pond? The fish is about 4 years old. I have attached videos and photos. any insight is helpful. I have scoured the internet and cannot find a photo quite like whats going on with my fish. Thank You!