Green Pea Tip
Whenever a fish has trouble swimming, it is said to have a buoyancy problem. Feeding affected goldfish a single green pea (canned or cooked and lightly crushed) once daily can help the problem in some cases. The "green pea" protocol should include increasing the water temperature to 75 to 80 degrees Fahrenheit and continued feeding of the regular commercial fish food (discontinue the feeding of floating pellets or flake food to the affected fish).
For more information, please read the article Buoyancy Problems.