One day I saw my goldfish, Finny, shivering around like a vibration. Then I saw a red patch of ripped off scales that made a stream of blood. My other goldfish, Orango, was trying to help. I don't think my koi fish or algae eater fish did it. They were really nice. I googled Itchy Scales and I found out about a parasite. I rushed Finny out of the tank and into a bucket. I put some towel wrapped ice on his side gently. He didn't make it. About 3 months later, Orango, Yoshii the koi fish, and Flick the algae eater got huge and my house had no space, so we gave them away.