Care of fish in biological research

Fish live in a very complex, dynamic environment. Their use as biological research subjects during the past three decades has increased almost exponentially because of the demand for an increased knowledge base in response to the need for better aquaculture technology. To use fish as biological research subjects requires the investigator to take into account approximately 40 interactive environmental variables, if the research data are to be free of unwanted biases. These environmental factors are classified into five major groups, all important to the well-being of fish. These five include intrinsic factors (fish associated) and extrinsic factors (water, container, nutrition, and management associated). The stress response is the primary intrinsic factor of concern, and associated pathological changes should be used to monitor animal well-being and prevent secondary infectious disease problems. The water-associated factors are the primary extrinsic factors affecting the well-being of fish. Thus, the investigator must design research protocols that maintain fish within documented environmental limits for the species.