Background. The use of anaesthetics in aquaculture requires conducting specific studies of their effects on fish. The objective of this study was to evaluate the effects of Propiscin (Polish agent containing etomidate) on common carp behaviour, heart rate, and ventilation. Materials and methods. Carp were anaesthetised with Propiscin at the concentrations of 1 and 2 mlּl-1. An electrocardiograph was used to record the heart rate and the amplitude and rate of the opercular movements. The effects of atropine and forced water flow over the gill system on the anaesthetised carp's heart rate were also studied. Results. At either concentration, Propiscin caused general anaesthesia manifesting itself in: a loss of equilibrium, faded responses to external stimuli, gradual ventilation failure, and bradycardia. A high correlation between respiration rate and heart rate was found in the anaesthetised fish. Conclusion. The hypoxia was the direct cause of bradycardia, and the regularity and amplitude of breathing are the most important indicators of the level of Propiscin-evoked anaesthesia.

fish, anaesthesia, Propiscin, etomidate, heart rate, ventilation, common carp