Sometimes, it’s not easy to spot if a fish is suffering from a certain disease or not. We can only assume based on their scales, the size of the belly, manifestation of white or red spots, and appearance of protruding eyes, among others.
An outbreak of disease in fishes can be widespread and it could happen that you’re not even aware of what this disease is. In this case, take note of specific changes you notice your fish started exhibiting such as changes in eating behaviour. For more information on common diseases in fishes, check out the following:
Bacterial Disease. This can be as simple as exposure to another fish that has a disease. This is a very common occurrence in fishes and sometimes, it’s difficult to deal with and understand. Manifestations of these diseases can be either outside or inside of the body and can enter through open areas of the fish such as the gills.
Common types of bacterial infection: body ulcers or lesions, thus, destroying the fish’s internal organs and rotting of the fins or tail.
Why this happens: Usually, it is due to parasites in the body, abrupt changes in aquarium temperature, and inferior water quality.
Viral Diseases. Common manifestations of viral diseases in fishes include protruding eyes, pale and bleeding eyes, discoloration of the fish’s body and scales. These are usually small infections that are not apparent so it’s harder to detect. But, as long as you know the symptoms and indications of a viral disease, you will be able to determine the correct treatment for it.
Non-Infectious Diseases. Although not contagious, just the presence of a “disease” can be disturbing to the owner. However, non-infectious diseases are usually caused by having high levels of ammonia in the water or low oxygen levels. They can further be categorized as due to environmental (high ammonia and nitrate in water), genetic (genetic abnormalities like being born without a fin or a tail), or nutritional (lack of vitamin C in the fish’s diet) factors.
Fungal Disease. If you see whitish or greyish spots on your fish’s skin, fins, or gills, then there is a possibility that it is suffering from a fungal disease. Watch out for possibilities of your fish experiencing breathing difficulties. If this is the case, then most likely, the gills have been infected already. In the long run, even healthy fishes will also suffer the same fate, that is, if you keep the healthy and sickly fishes together in one aquarium.