The effect of stocking densities on total bacterial count in walking catfish, Clarias batrachus

This study was carried out to examine the effects of stocking density on the total bacterial count in walking catfish (Clarias batrachus), cultured in a closed system for seven days. Three different stocking densities were tested; Tank A consist of three fish per tank, Tank B contained six fish per tank and Tank C contained nine fish per tank, all with volume of 0.135 cm3, each having three replicate. Fishes in all experimental tanks were given commercial starter pellet ad libitum and reared in suitable water parameter. Sampling of the fishes was done on day-two, day-five and day-seven of the culture period. Upon sampling, three catfishes were randomly chose and dissected to isolate the bacteria by using 10-fold serial dilution method. The bacterial colony forming unit (CFU) isolated from fish in Tank A had increased to 0.81 x 10⁶CFU/ml from day-zero (0.75 x 10⁶ CFU/ml), decreased at day-five (0.78 X 10⁶ CFU/ml) and then slightly increased at day-seven (0.83 x 10⁶ CFU/ml). Tank B had bacterial amount increases constantly which were 0.79 X 10⁶ CFU/ml. 0.96 X 10⁶CFU/ml. and 1.01 X 10⁶CFU/ml at day-two, day five and day-seven. respectively. Tank C had CFU increases until day-five (0.80 x 10⁶ CFU/ml to 1.15 x 10⁶ CFU/ml) and then decreased slightly at day-seven (0.96 x 10⁶ CFU/ml). The bacteria that has been identified were Staphylococcus sp., Aeromonas sp., and Edwardsiella .sp..