© Paul Atkinson / stock.adobe.com
A yellow Pyramid Butterflyfish with small growths on its fins and body, which might indicate the presence of Lymphocystis disease in fish.
Discover what triggers nodular disease in fish, its dangers, and what actions to take if you spot lumps on your fish’s body in this friendly guide.
Nodular disease is a parasitic fish disease. When a fish gets infected, variously sized nodules form in its muscles and on internal organs.
The disease poses threats not only to the infected aquarium fish but also to their tank mates. Firstly, there is no cure for the disease. Secondly, the disease can spread to other fish through free spores in the water.
Fish of many different species can be afflicted with nodular disease. The species affected depends on the type of pathogen:
Myxosporidia typically form nodules, also called cysts, on affected fish. The parasites spread within the fish over time, as the nodules grow and multiply.
The shape and size of the lumps vary among species. Most nodules are round, but they can also be oviform or worm-like.
Their sizes range from a few millimetres to one centimetre. The nodules of many species are white, but in some cases, they could have different colours or be translucent.
If you observe any of the symptoms mentioned above in your fish, it’s important to isolate the affected individuals as swiftly as possible and consult your veterinarian. This is crucial in the case of nodular disease to contain the spread of the infection in your tank.
© besjunior / stock.adobe.com
To distinguish nodular disease from similar-looking diseases such as trematode worm infestation, your vet will carry out a microscopic examination of the nodule content.
Firstly, the nodule is carefully removed by hand or with a scalpel. Then, the nodule is crushed, and the released spores are searched for under a microscope, which indicate nodular disease.
Reports suggest that nodules can be removed, and the spores killed by irradiation. Toltrazuril is also said to help against certain types of sporozoans.
However, there is currently no widely recommended treatment for nodular disease in fish. Therefore, always follow the guidance of your veterinarian.
Furthermore, it is wise to remove the affected fish from the aquarium and place them in a quarantine tank. This way, you protect other animals from becoming infected with the nodular disease.
The culprits behind nodular disease are certain parasites known as myxosporidia. There are many different genera of these single-celled organisms:
In practical terms, Henneguya and Myxobolus are the most common in fish.
Note: Nodular disease should not be confused with the viral lymphocystis, also known as nodular disease.
Although the various genera of pathogens undergo individual developmental processes, they have one thing in common: they all produce spores.
Some species require the help of intermediate hosts, such as the mud tube worm. Sometimes, transmission occurs directly from one fish to another:
If you detect the nodules early and move the affected fish to a quarantine tank, the bursting wounds can gradually heal. Here, husbandry and feeding play a significant role.
Despite your best efforts, it may still occur that sick animals die from the consequences of the infection or need to be euthanised by the vet.
© Czanner / stock.adobe.com
It’s impossible to completely eliminate the risk of infection with myxosporidia. However, to prevent infections in general, you should adhere to recommended living conditions and dietary guidelines for the fish species in your aquarium.
Also, regularly monitor the health of your fish by observing not just their appearance but also their behaviour. The sooner you recognise changes, the earlier you can intervene in the event of a nodular disease infection and assist your fish.
At the Justus-Liebig-University of Giessen I was extensively trained as a veterinarian and was able to gain experience in various fields such as small animal, large animal and exotic animal medicine as well as pharmacology, pathology and food hygiene. Since then, I have been working not only as a veterinary author, but also on my scientifically driven dissertation. My goal is to better protect animals from pathogenic bacterial organisms in the future. Besides my veterinary knowledge, I also share my own experiences as a happy dog owner and can thus understand and enlighten fears and problems as well as other important questions about animal health.
Are you looking for new carps (Cyprinus carpio) for your pond? Then you should definitely consider the Butterfly Koi. Read in this article the most important information on this beautiful Koi.
Blue algae looks like a green-blue carpet which can cover plants, decorations, and the bottom layer of the aquarium. Not only are they an eyesore, but blue-green algae can pose a significant risk to all forms of life in the aquarium. But what actually are they, and how do they grow? Read on to find out how to effectively combat and prevent the build-up.
Aquarium enthusiasts and animal-loving anglers might at some point ponder: do fish feel pain? Since fish can't speak, finding a satisfactory answer is not straightforward. However, a foray into science does offer better insight into the pain perception of fish.
