1, reason: goldfish have no stomach, so they cannot be fed too much at one time. If they are fed too much, they will have flatulence in their abdomen. In this way, they won't eat any more, which is not conducive to their health.

2. Treatment method: Put proper amount of garlic and salt or oxytetracycline in the fish tank, crush and sprinkle into the fish tank. Once a day, their flatulence will be cured in about three days, and then they will eat again.

1. Reason: Although goldfish belong to wide-temperature fish, their requirements for water quality are not high. However, they can't adapt to the environment with sudden changes in water quality. Once they change suddenly, they will have a series of adverse reactions, such as not eating.

2. Treatment: Explode oxygen and add salt. Using an oxygen pump to pump a large amount of oxygen into the water can improve their metabolic ability, thus making their symptoms disappear. Sudden changes in water quality will make them eat nothing, which may make their physique worse, so adding salt can effectively prevent bacterial infection.

1. Cause: When water is polluted, they get sick. At this point, they won't eat.

2. Treatment method: Change water in time. But don't change too much water every time, change about one third every time.