Dropsy is another name for bloat. A goldfish suffering from an advanced case of dropsy will puff up, and its scales will stick out like a pine cone. The causes can be varied, ranging from bacterial infections to viral infections or even parasites. The balloon-like appearance of the fish is due to swelling brought on by the kidneys filling with fluid. The damage at this point is usually beyond repair, but if you wish to attempt to treat it, using Epsom salt is a viable option. Epsom salt helps extract fluids into the stomach where they can pass, relieving the bloating.
Set up a hospital tank the appropriate size for the sick fish.
Remove the infected goldfish from the main tank and place it into the hospital tank.
Add one-eighth of a teaspoon of Epsom salt per five gallons of water.
Monitor the fish and repeat step three as needed when adding more water until symptoms improve.
Return goldfish to original tank once dropsy is cured.
Dropsy can take two weeks to one month to cure.
Do not use more than 1.25 teaspoons of Epsom salts per five gallons of water. A little goes a long way.