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The need to enhance the quality of fish feed produced in Nigeria was the major consideration in the design and development of a preconditioning system. The machine consists of two insulated cylindrical barrels, set of arranged paddles on a shaft, frame, hot water and feed mash inlet, discharge chute, chain and sprocket. It was powered by a three-phase 15 hp electric motor which transmits power to the machines shaft and set of paddles via chain and sprocket. The performance characteristics of the machine; mixing efficiency and throughput capacity were evaluated using Nigerian Institute for Oceanography and Marine Research (NIOMR) feed formulation at feed mash particle sizes of 900 µm, 550 µm, 520 µm and paired paddle rotating speed of the lower and upper chamber at (96.8; 145.2), (122.6; 183.2) and (174.5; 260.8) rpm respectively. The throughput capacity of the preconditioner is 650 kg/hr. The results showed increase in temperature and moisture content level of the particles as the machine speed decreases. The optimum mixing efficiency that gave best uniformity of mix was attained when Paired paddle speeds were (96.8; 145.2), (122.6; 183.2) with an average Biot numbers of 0.1.