In optimizing controlled fish production, a number of parameters directly related to the stocking density, including water quality, fish nutrition and the size- physiological stage of the fish, the type of production system, and the type and size of the rearing tanks, must be considered (Malison and Held, 1992; Tidwell and Webster, 1993; Bagley et al., 1994; Papoutsoglou et al., 1998). High stocking density can affect fish performance and welfare through crowding stress, and/or through water quality deterioration in recirculating systems. As compared to water recirculation, daily water exchange was insufficient in the concrete pond. Under practical conditions, high stocking density often coincides with reduced water quality, so decreased growth was attributed to the combined effects of fish crowding and water quality deterioration (Santos et al., 2010).