Water Renewal Frequency Affects Water Quality, Growth Performane and Physiological Staus of African Catfish, <i>Clarias gariepinus</i> Juveniles

Abstract

A 56-day experiment was undertaken to assess the influence of water changing frequency on the water quality, growth performance and physiological status of African catfish, Clarias gariepinus juveniles. There were three treatments with different water changing regimes, every two days, every four days and once a week. Nine plastic tanks were stocked with ten African catfish (10.39±0.36 g) each in triplicates for the three treatments. The fish were fed at 5% body weight daily. Selected water quality parameters were examined twice a week, while growth performance and physiological parameters were measured at the end of the eight weeks. pH, temperature and nitrate-nitrogen were not different significantly among the treatments. The highest total ammonia-nitrogen (0.55±0.01 mg L-1 ) was observed in the treatment with water changes once a week, and it was significantly higher than the treatment with water changes every two days. Both total dissolved solids and electrical conductivity were also different among the treatments. Growth performance improved with decreased frequency of changing water; weight gain, specific growth rate and yield were all higher significantly in the treatment with water changes once in a week compared to every two days. Nutrient utilization, survival and body indices were not different significantly among the treatments. Higher glycogen and healthier livers were noted in the treatment with water changes once a week. The result established that changing the water once a week for fish stocked up to 20 Kg m-3 may confer more advantages on the fish and lead to improved performance.