The fish health work-up an invaluable step by step guide to diagnosis health problems and their causes. Although it is impossible to make a diagnosis based purely on behaviour we can use typical behaviour and physical changes as indicators of possible health problems. The fish louse. A real nasty. In the confines of a pond or tank these can be real killers and finding even one louse warrants immediate treatment.
Bacterial infections including fin rot and ulcers are a serious threat to health.
Bacterial gill disease is usually a 'management' problem, arising from less than ideal conditions. Chilodonella a common parasite, often occurring at low temperatures. It is a threat as it often causes severe damage before any signs are evident. Costia is able to reproduce rapidly under ideal conditions and cause serious tissue damage, particularly in the gills. Fin rot With few exceptions, fin rot is always precipitated by stress and is often one of the first signs that a health problem exists.