|Dropsy, Pic Usakoi.com|
Sometimes it's not contageous, but sick fish should be isolated and treated since determining the actual cause may be impossible. The swelling is because the fish is absorbing water faster than it can eliminate it, and it can be caused by many different problems. High nitrates are one thing to check. Internal bacterial infections, including fish TB, are other possibilities. If there are no water quality problems, you may want to attempt antibiotic treatment in a separate tank.
There are multiple possible causes. Usually caused by kidney damage. Kidney damage may be caused by overuse of drugs or a disease. Eventually the swelling will cause the scales to raise, giving the fish what is called the "pine-cone" appearance.
You can best see this by viewing your fish from the top. Fish may also stop feeding, appear off-colour, become listless and/or lethargic, have sunken eyes, and hang at the top or stay at the bottom of the aquarium.
Recognizing Dropsy DiseaseWhat makes dropsy so hard to diagnose in time to treat it is that the symptoms that we know as dropsy do not come out until the fish has entered the final stages of the disease. The fish literally blows up like a balloon. Its scales stick out, making the fish resemble a pinecone. In fact, Dropsy is often called Pinecone Disease because of it. The eyes will bulge out from the trapped fluids beneath.
Dropsy is also often accompanied by external bacterial infections including fin rot, mouth rot and ulcers. In some cases I've seen almost any and all symptoms. It's really a sad sight to see.
This poor little fellow died from dropsy this morning. You can see how his breast area is swollen and his scales are sticking out. His eyes never bulged out but he had fin rot, ulcers and his skin and fins were riddled with red streaks and swollen blood vessels.
Preventing DropsyPoor water conditions are often the culprit. Gouramies, Cyprinids (barbs, danios, etc), guppies, betta and goldfish are prone to this disease. Goldfish are said to be somewhat more prone to dropsy than other fish. High nitrates are usually the culprit. Clean Water, is a must! Clean Water, should I say that again? Good water conditions prevent this.
Excellent water quality is probably the one best thing we can have to prevent dropsy, though sometimes no matter what you do a dropsy case will still happen. A pond can never have too much biological filtration. Make sure the filter you have is sufficient (and even more than sufficient) for your fish load. We use the ProBead because it gives us excellent water quality and low-maintenance.
In early spring we like to treat our pond for parasites as well as start our koi out with two weeks of triple antibiotic food -- even if the fish are showing no symptoms of parasitic or bacterial problems. This is a precaution that pays off well in prevention of disease, including dropsy.
Treatment DropsyDropsy is not very contagious; however, Fish usually die from this, but in some cases where the problem is due to bacteria, if detected early enough, it can be treated.
It's possibly the hardest internal bacterial infection to cure. There are a number of medications available such as penicillin, tetracycline and naladixic acid. The fish usually doesn't make it. By the time the scales begin to raise, however, it is very fatal to the fish. Salt baths can help to draw the fluid out of the fish. A variety of medications can be purchased that treat dropsy, which sometimes occurs due to an internal bacterial problem. Medications for external bacterial problems only will not be effective for this problem.