1. Reason: The fin congestion of goldfish may be caused by the deterioration of water quality. If the breeder does not change water for a long time, the pH value in the water changes too much and the dissolved oxygen is too much, it will lead to fin congestion.

2. Solution: Breeders need to change water immediately to keep the water clean. And immediately adjust the pH value of the water to keep it in a stable range. Finally, a small amount of water is changed every day, so as to ensure that their fins can be restored.

1. Reason: The congestion of goldfish fins may also be caused by too large a temperature change. When the water temperature in the fish tank suddenly changes greatly, it will stimulate their fins and lead to congestion.

2. Solution: Breeders need to install a heating rod to keep the water temperature in a stable range. After the water temperature is constant, the congestion of fins can be restored.

1. Reason: Goldfish fin congestion may also be caused by stress response. When goldfish are frightened or stimulated, their fins will be congested.

2, Solution: Breeders need to move them to a quiet, dark environment and wait for them to recover.

1. Reason: Goldfish fin congestion may also be suffering from scalding tail disease, mainly because the water temperature in the upper layer is too high, which leads to their fins being scalded and infected.

2. Solution: Breeders need to clean up the blisters on their fins and transfer goldfish to fresh water, which can recover in about one night.