What Ranchu Lover said is very true, and very important. The third picture is a picture of fish that has been in treatment for a bit, but still show some symptoms. This is why it is very important to try to inspect your fish often. When you know what healthy gill looks like, it is easier to diagnose a sickness. Early detection and proper medication are keys towards full recovery.

I understand that it is very difficult to see the subtle changes in your fish. But this is very important. An expert or an attentive keeper will be able to tell exactly when their fish starts to act weird. You can usually detect if the fish is getting sick from the changing of the behavior, long before you can diagnose from the symptoms. Just like people, ranchu get groggy and do not want to swim when they are sick. They will also loose their appetite. When the fish loose their appetite (unusual amount of left over food which usually do not occur), it also may be sick.

Some ailments (such as white spots which is caused by a viral infection), if and when you see the symptoms (white spots appearing all over), then it's too late. All you can do is flush the whole tub so that you don't spread the disease to your other fish.

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