Dropsy is a symptom of an issue more then an actual disease.
Often it is the last stage of a serious internal bacterial infection.
You could do epsom salt baths if you choose ,but often by the time you see the severe pine coning internal damage on the fish is too great already.
Of the few who actually documented recovery from full on dropsy ,it only re occurred until the fish finally could recover no more..Much like non injury pop eye...
Look to water parameters first and then watch other fish if any closely.
Sorry I can't offer more hope,Epsom baths are easily found in a search.
