Handling Specific Problems

There are two broad categories of disease that affect fish, infectious and non-infectious. Infectious diseases are caused by pathogenic organisms present in the environment or carried by other fish and are broadly categorised as parasitic, bacterial or fungal. They are contagious, and some type of treatment will be necessary to control the disease outbreak. In contrast, environmental problems, nutritional deficiencies, or genetic anomalies cause non-infectious diseases, they are not contagious and cannot be cured by medications.

It is impracticable to cover all the diseases that rainbowfishes are capable of catching in an aquarium. There are many good books readily available on fish diseases and their treatment. However, I will cover some of the common diseases that you, or rather your rainbowfishes, are likely to encounter. Fish disease outbreaks are often complexed, involving both infectious and non-infectious processes. Therefore, appropriate therapy often involves medication and changes in husbandry practises. Often assistance from a qualified veterinarian or aquarium specialist will be required to help you treat disease outbreaks and develop a management program.

Compared to mammalian diseases relatively little (and in most cases very little) is known about individual fish diseases. The biology of most fish diseases (how they can spread, how infective they are etc.), especially those of rainbowfishes, is little understood, and thus assessments of and solutions to the problems they can cause is, at this point of time, based on incomplete information.

Fish health has been a relatively small discipline of veterinary attention in the past because of many factors, the most important of which is the perceived value of aquarium fish. Other reasons include the failure of pharmaceutical companies to become involved in ornamental fish health, or a failure of the standard of health care to keep pace with improvements seen in the care of other companion animals. This though is not the fault of veterinarians. The fact is that veterinary surgeons are often reluctant to treat fish and will often prefer to call on the help of a specialist. There is some justification for this reaction since fish do present particular difficulties with regard to both diagnosis and treatment. Clinical signs in fish tend not to be as specific or as easy to observe as in mammals, and the use of thermometers and stethoscopes is not an option for fish.

There also tends to be a heavier reliance on laboratory techniques in diagnosis. Nonetheless, as more people invest in expensive species, such as koi and various reef species, the demand to provide a higher level of care for these animals is increasing. This trend is also evident in the commercial food and bait fish industry, where aquaculture producers are expecting improved standards of care for populations of fish that are worth millions of dollars. With increasing numbers of aquaculture operations, aquarium traders, and those involved in public aquaria veterinarians will be expected to have the abilities and knowledge to diagnose and treat aquatic species and provide a standard of care commensurate with other commonly treated animal species.