There are a number of common tropical fish diseases, some of which may occur in spite of careful husbandry. Among them are:
• Dropsy; this abdominal swelling is among the most common tropical fish diseases currently observed in residential fish tanks. The fish appears listless, it is bloated, and it ceases a majority of movement. Bacteria are to blame for this condition and while it is not always fatal, the outlook for fish suffering from dropsy is not good. Specially formulated anti bacterial water additives may be used in the early stages of the disease to reverse the effects.
• Fungal infections are also among common tropical fish diseases. Sometimes described as fin rot, the fungal infection leaves the fish fins ragged looking and in some cases with holes or missing pieces. If not caught at this stage, the fungus will go on to attack the rest of the animal’s body. Readily available water additives may be purchased to counteract the fungus, its effect on the fish, and also to hearten the animals’ overall health for future protection.
• Hole in the head is one of the common tropical fish diseases that affect clownfish and also lion fish. It is disputed what may cause the skin abrasions that give way to lesion growth, although it has been speculated that in some cases this may be due to a mix of carbon particles in the water and the presence of bacteria. Frequent water changes and a vitamin rich diet are indicated in the prevention of this disease.