Dave I agree, I've read that it is not contagious. Let one die in a pond and start decaying, Almost certain another will follow. What actually causes dropsy. There are more than one thing that can cause it and very little can be done once a fish has it. It forms from a build up of gasses usually formed from infection within the airbladder or intestinal tracts. Could be caused from bacteria, viral funus, and even bad food. Most of the time Dropsy attacks fish that aren't in the best water conditions at some point in time. Not necessarily though at that particular time.
Normally Larkin if I can remember it correctly that is not in acctual fact true, as it can be caused by a number of conditions.
It can be bacterial or caused by ogan failure like the kindney stopping it functionng however in a worst case senario it is also viral and in this case a number of other fish may go down with it at the same time,
Thats the Bacterial and Viral dropsy taken care of my friend but there is however yet another form and that caused by a Parasite that attacks the fishes kidneys causing them to enlarge and because of this loosing their ability to function, in all cases of dropsy QTing your fish is the most sensible option
The simplest form of dropsy is simple fluid retention however salt can cause the fluid to be released and your fish go back to normal, normally you'll see your fish at the surface or close to areas of high oygenation they will nines out of ten stop eating.
Salt should be your first treatment at a level of around 10-13 lb per 220 gallons or one ton of water or for you metric minded folk 5-6 kg per 1,000 ltrs for a period of around five days longer if no improvement is seen
To this salt mix you can add an anti bacteria like acriflavin however you shouldnt be dis hearted if you loose a fish , its all down to when you first noticed it and got it into treatment , like I previously stated you can win through however this problem may occur , if however there is no change it would be advisable then to painlessly euthanize the fish in question
Studiovette I hope this helps in your understanding of dropsy and you win through with this fish
Dave