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. |
University of Cape Coast