The health and consequent growth of fish are related to the quality of water in which the fish are lift. The factors affecting fish growth and production in freshwater aquatic systems can be classified as physical, chemical/biochemical, or a combination of them. The physical properties of water that are significant to fish production and growth comprise temperature and the concentrations of suspended and settleable solids; significant chemical parameters include pH, alkalinity, hardness and metals.

Dear Raja Abd Ali Al-Mudhaffar 

The health and subsequent growth of fish are directly related to the quality of water in which the fish are raised. In general, factors affecting fish growth and production in freshwater aquatic systems can be classified as physical, chemical/biochemical, or a combination thereof. The physical properties of water that are important to fish production and growth include temperature and the concentrations of suspended and settleable solids; important chemical parameters include pH, alkalinity, hardness, and metals.

Water temperature is one of the most important physical factors affecting fish growth and production. Fish are cold-blooded animals which assume approximately the same temperature as their surroundings. Typically, fish are classified broadly as cold, cool, or warm water, depending on their tolerance for particular temperature ranges. Within each temperature classification, fish survival is bounded by an upper and lower temperature, between which an optimum temperature for growth exists. When temperatures vary outside the optimum range, decreased tolerance to changes in water quality constituents (particularly metabolites such as ammonia) and a decrease in immunological response can occur. Consequently, decreased growth/productivity and in some cases, mortalities, may result, depending on the magnitude of the deviation from the optimum temperature. For example, the survivable temperature range for rainbow trout (Oncorhynchus mykiss) is ∼1 to 26°C. However, depending on the reference source, the “optimum” temperature range for growth is 13 to 21°C.

Regards 

Dear Rajaa,

From the view point of bioenergetics, every stressful factor including diseases, parasites, environmental or physiological stressors, will mean energy loss in maintaining homeostasis which otherwise is dedicated to support the growth of new body tissues. Therefore, fish can not gain extra growth unless it live in a good health.

Best regards

SM Najim