The reasons why goldfish lose their eyes:
1. Fighting
If there are too many goldfish and they fight each other, they may peck out each other's eyes. In this case, the goldfish that has lost its eyes should be kept alone.
2. Parasites

When a goldfish’s eyes are infected with parasites, it will also cause the eyeballs to fall off. The parasites should be cleaned up in time and the goldfish should be given a medicated bath with potassium permanganate.
3. Bacteria
Goldfish eyes falling out may be caused by bacterial infection. When the water quality is too poor, bacteria will breed. The water needs to be changed immediately to keep the water clean.
4. Stabbing
If there are some sharp objects in the fish tank, it is easy to sting the goldfish's eyes, causing the eyes to fall off. Pay attention to checking for hidden dangers in the fish tank.
5. Lighting
If the lighting is uneven and strong light shines directly on one location for a long time, the goldfish will avoid light, swim sideways, and its eyes may fall off, so the light in the fish tank needs to be kept uniform.