Definition and symptoms
Abdominal dropsy / Ascites is a common infectious disease in which there is an accumulation of fluid in the abdominal cavity of fish. The disease can affect any species of fish, but mostly fish with a reduced immune system are affected. Abdominal dropsy is highly contagious and can spread to the other fish in the stock. Without timely treatment, the disease is fatal.
The fish appear bloated, the eyes may protrude and the scales stand off the body. Due to the filling of the abdominal cavity, the fish are impaired in their swimming movements. They either remain at the bottom or stay at the water surface.
Below is a list of the most common symptoms of abdominal dropsy:
- liquid-filled stomach
- Apathy and reduced escape behaviour
- Exophthalmus (protruding eyes)
- uncontrolled swimming movements
- Staying on the ground or on the water surface
- Skin inflammation
- Excretion of mucous feces with parts of the intestinal mucosa
Photos and videos for comparison
© Janina Stampf
Dropsy neon tetra © Karolin Wisch
Causes of dropsy
Although dropsy is considered an infectious disease, the pathogen has not yet been identified.
It is assumed to be a viral or bacterial disease. What is certain is that bacteria are involved that are found in the substrate and water of the aquarium. The genera Aeromonas and Pseudonomas were identified.
Under normal circumstances these bacteria are harmless, but in sick or weakened fish they can act as opportunistic pathogens.
Fish that are exposed to stress – for example due to poor water quality, poor nutrition or insufficient care – are more likely to develop dropsy.
Course of the disease
The disease is usually noticed when the fish increases in girth and begins to show uncoordinated swimming movements. The protrusion of the eyes is also evident in the early course of the disease. At this stage treatment is often successful. The further the disease progresses, the less likely the fish is to survive. In the further course of the disease, inflammation of the skin becomes apparent. Ulcers can form. Secondary it can come to a fungal attack. If the fish begins to excrete light-coloured faeces containing parts of mucous membrane, it can be assumed that the internal organs are severely affected. If no treatment is given, the fish will die of kidney failure.
Treatment of dropsy
If you notice the symptoms of dropsy in your fish, you should immediately separate it from the other fish and put it in a Quarantine tank implement. The pathogens that are excreted with the faeces will otherwise get into the water and the other fish can be infected.
A therapy for dropsy can be tried if the disease is diagnosed early. The active ingredient nifurpirinol is often used for treatment. Furthermore Salt baths will be used. For this purpose, 1 to 5 grams of salt is dissolved in 1 litre of water and the fish is bathed in it. Find out beforehand what salt content your fish tolerates. The bath helps the fish to release the accumulated liquid. It can also reduce the density of pathogens. After the treatment a Partial water change and the oxygen content and temperature should be slightly increased.
The treatment procedure in short form:
- Transfer fish to a quarantine tank (ideally with alder cones)
- rapid treatment with an appropriate drug, for example with the furan nifurpirinol
- additional salt baths
- Partial water change
- slight increase of oxygen content and temperature