The Goldfish Sanctuary
Symptoms: Fish's abdomen becomes unusually large and swollen, scales may stick out
Dropsy is not, in itself, a specific disease, but rather refers to a condition where the fish's abdomen becomes swollen. A sudden swelling of the abdomen (scales may stick out) is known as acute dropsy while a slow swelling of the abdomen is known as chronic dropsy. The actual cause of this swelling could be indicitive of any one of several conditions:
Acute Dropsy - septicemia: Internal bacterial infection can cause internal bleeding and thus cause acute dropsy. (See septicemia).
Chronic Dropsy - cancer: In this case, the abdomen is slow to swell as the cancer affects the fish's internal organs. If the fish is not isolated in the early stages of the disease, it could spread to other fish.
Chronic Dropsy - parasites: Internal parasites can cause dropsy (abdominal swelling) either because they are very large, or because of the damage they are causing to a fish's organs. The abdomen tends to swell gradually if the fish has internal parasites. Isolating the fish helps prevent the spread of the condition.
Other Dropsy: There are other less common causes for both acute and chronic dropsy, and not all causes are known. Your vet will provide additional details.
Goldfish are said to be somewhat more prone to dropsy than other fish.
The first task is to begin medicating the tank with an antibiotic in order to remove the initial cause of the dropsy.
During the time that your antibiotics are active, your fish should have 2 to 3 one-hour brine treatment sessions a day. This will help break the fluid bond, and speed recovery.
THE ONE HOUR TREATMENT SESSION - Within the one-hour time period, your fish should be bathed 2 to 3 times in the brine solution. During one bathing, the fish should only be left in the solution until he shows signs of stress (usually 2 to 4 minutes) and then returned to the medicated tank.
MAKING THE BRINE SOLUTION - The solution should be 4 tablespoons of brine salt to one gallon of water for the short-term baths.
When antibiotic treatment is over, discontinue any further treatment for 7 days. During this 7-day period, 1 tablespoon of salt can be added to the tank per 5 gallons of water. Treatment may be repeated after this 7-day period if the dropsy does not disappear.