Aquaculture ecosystems are aquatic environments that tend to be unstable and unnatural. In general, the greater the intensity of cultivation, the greater the instability of the environment. All environmental components (physical, chemical, and biological) are subject to constant change. In intensive aquaculture, many factors can stimulate physiological or stress responses in cultured fish. Stress is defined as the effect of any change in the environment or the drive to achieve homeostasis or change instability to reach its normal limit. Stress that occurs in fish is related to the onset of disease in these fish. In order to give satisfactory results, the selection of this preventive technique must be adapted to the environmental conditions. Several disease prevention measures that need to be taken have been described in detail in this book.
