It depends on what's causing it. Dropsy is actually a symptom, not a disease.
So yeah, there may be a cure
First fast him for a day and the next day try feeding a skinned and boiled pea.
If that doesn't do it then it may be an internal infection in which case treating him will be trickier.
Is he really bloated? Or just a little? Also, did this suddenly happen or has he been slowly getting worse? Is he pine coning at all?
If he doesn't get better from fasting I would try a salt bath. Use Epsom salt rather then regular aquarium salt. The general accepted rule tends to be 1 tablespoon per gallon. Prepare a small container (make sure the water is the same temperature as the tank...in fact, you may want to use tank water) and add the epsom salts to the water. Then you put the goldfish into the container and leave him there for 5-10 minutes. Watch to make sure he doesn't completely freak out although it's normal for him to be stressed out. While he's in the bath I'd do a water change on the hospital tank so when he goes back to his home it's nice and clean. You can give him a salt bath twice a day and I would try it several times over the next few days.
Keep up on water changes and if you have a tank heater I would raise the temperature into the low 80's. It will help if he ends up having parasites. If he does have parasites you should feed an anti-parasite food and add aquarium salt to the tank.
You can use a medication (sorry, I don't know what's available in Canada) made for internal
infections as well. But I wouldn't medicate just yet and if you do make sure to start with small doses. You don't want to stress him out too much and using the wrong meds or large doses may cause liver damage and make things worse.
Oh, and have you netted him recently? Or saw him crash into something? Occasionally dropsy is caused by injuries.
Don't feel bad, either. Remember that dropsy is unfortunately rather common in goldfish...especially the fancy varieties.