Ich is one of the most common sicknesses that fish come down with. The treatment is to sometimes add some extra heat and use a little tap water for goldfish.
There are several common goldfish illnesses known. Freshwater white spot disease, Fin rot, Fungus, Dropsy, and Pop eye are just a few of the most well known diseases in goldfish. Most illnesses relate to tank conditions, so the best course of action is to first test your water for possible causes. Temperature, filtration, and oxygen levels are all causes.
The most common goldfish sicknesses are anchor worm, bacterial infections, black spot, cloudy eye, fungus, tail and fin rot, skin flukes, ulcers, fish lice, dropsy, costia, constipation, and flipover disease.
Common goldfish can have various things from ulcers to anchor worm, or it could just be sick from a temprature change in the water. It would be best to talk to someone that works with fish in your local pet store, they can help.
