Pond/koi fish

Question
I have 2 questions. I have a fish that I believe is a goldfish.  I believe at one time, this fish did have color to it but is now completly white in color. (not sure why) This fish had both of it's eyes fall out about 2 weeks ago. I know it's gross but I have no idea why or what happened.  I have a 2 year old koi which is my largest fish in the tank (among the others) which appears to always be 'picking' on the white goldfish and doesn't seem to both any of the other fish. The white fish is always trying to get away from the Koi even though it can't see. Is this an indication that the white fish is sick and that the Koi knows it?  I have tried to research why the fish lost it's eyes but haven't seemed to come up with an answer. I know there is a eye disease that may cause that but I don't recall the fish having any cloudy or bubble to the eyes.  None of my other fish have this problem.

Answer
Marcie,                                                      Your large koi may have bitten them out. If you saw them at the bottom of the tank it was probably a bacterial infection called pop-eye.Though this does not come on that suddenly. You can see the eyes start to protrude before it happens. I don't know if the fish you have is a goldfish. Color changes are common with them, but also not that quickly. Have your other fish been with him a long time. Sometimes when fish become dominant in a tank they do not like newcommers. Anyway if it is still alive and even if not just to make sure everyone else will be ok treat your tank with a broad spectrum antibiotic like tetracycline. Don't forget to remove your carbon. After 7 days replace with new carbon and a 30% water change. Take your other fishy out and quarantine it. Treat it also. Good Luck,Tina