I have gotten my ranchu goldfish 2 months ago. Before I got him he survived a flesh eating bacteria on his back, but made a full recovery. The only thing was is cloudyness in his eyes. The vendor told me it will go away, but it didnt. I tried to treat him for infections, fungus, gave him vitamin D supplements after visiting a vet multiple times, but none of this helped Beside the visual part of it he is a very active and happy goldfish, but it still worries me.