ANAESTHETIC EFFICACY OF 2-PHENOXYETHANOL IN FINGERLINGS OF KOI CARP Cyprinus carpio

The transport of live fishes has become an important aquaculture practice. Because of live fish trade, especially the live ornamental fish is emerging as a major business venture. Use of anaesthetics with optimum concentration could mitigate the stress and its related harm in fish, by increasing fish welfare, production and profitability.

Efficacy of 2-phenoxyetyhanol for koi carp fingerlings exposed to four concentrations (100µlL^-1, 200µlL^-1, 300µlL^-1 and 400 µlL^-1) were evaluated. The time periods necessary for induction and recovery of each concentration were recorded. Water quality parameters were recorded in all the four concentrations and control: Temperature (27.6±0.19°C), DO (5.54±0.52 mg/l), CO₂ (5.44±0.93 mg/l)_, Salinity (1.12±0.50) and pH (7.36±0.10). Results showed that, there was significant difference (P<0.05) of induction time between concentrations of 100µlL^-1, 200µlL^-1, 300µlL^-1 and 400 µlL^-1. The induction time was decreased with the increased concentration of 2-phenoxyethanol. Recovery time also showed concomitant difference (P<0.05) with the concentration of 100µlL^-1, 200µlL^-1, 300µlL^-1 and 400 µlL^-1. Concentration of 300µlL^-1 (induction time: 4.07±0.03 seconds and recovery time: 15.03±0.01seconds) was determined as the minimum effective concentration that induced anaesthesia and transportation of koi carp fingerlings (Table 1 & 2).