Goldfish are very sensitive and should not be touched. This can hurt them and make them sick. They may also get other health problems. Their stomachs can fill with liquids (water). They can get sick because of bad bacteria. Some lose control of swimming because a special organ in their belly, called a swim bladder, gets sick and stops working. However, sick goldfishes can be cured with medicine. Pet shops or veterinarians can help goldfish get better when they are sick. One simple way to help a goldfish if it has indigestion is to feed it peas, as this will help their digestive tract work properly.