Experimental xylazine-ketamine anesthesia in the common carp (Cyprinus carpio)

The potential anesthetic effect of ketamine in combination with xylazine was examined in the common carp (Cyprinus carpio). Anesthesia (indicated by cessation of voluntary swimming and loss of responses to pinching the skin with forceps and pricking the tail with a needle) was induced by mixing 14.4 ml of ketamine (5% solution), or 11.4 ml of xylazine (2% solution), or both, in 10 l of water containing 10 fish/group. Xylazine alone induced sedation and anesthesia in 5-12.3 min with a mean duration of 7.3 min. Ketamine alone induced similar effects in 7.2-9.7 min for an average of 24.2 min. Combined xylazine and ketamine took longer (14-22.8 min) to induce sedation and anesthesia, but the duration was longer (42.7 min). The respiratory rates of anesthetized fish significantly decreased in all treatments when compared to controls. In conclusion, the combination of xylazine-ketamine was found to induce smooth anesthesia in the common carp for a time sufficient for common clinical and surgical interventions.