1. Reason: Goldfish may lose their eyes because of parasitic infection, and the parasite that their eyes are often infected with is trematode. These parasites often enter the eyes of goldfish, which not only causes the eyes to fall off, but also may cause the eyeballs to fall off.

2. Treatment: If parasites in eyes can be found, they need to be cleaned with tweezers first. Then use trichlorfon or potassium permanganate to give goldfish a medicinal bath, about 3 days, and the eye drop can be alleviated.

1. Reason: Goldfish may lose their eyes because of bacterial infection. Their eyes are fragile and they are easily infected with bacteria. For example, if the water quality they live in is too poor, their eyes will be infected with bacteria. Or if the food is fed with bacteria, it will also cause them to have bacterial infection.

2. Treatment: Breeders need to fish out infected goldfish to prevent them from spreading to other fish. The second is to change water for goldfish and keep the water quality clean. Finally, five thousandths of crude salt is added for sterilization.

1. Reason: Goldfish's eyes may also be caused by fighting injuries. Although they are gentle, they can also fight. After a fight, it is easy to get hurt in your eyes.

2. Treatment: Breeders should first apply chlortetracycline ointment around their eyes to avoid bacterial infection, and then give them a medicinal bath with yellow powder, which can sterilize and disinfect.