The Effectiveness of Ketamine as an Anesthetic for Fish (Rainbow Trout – Oncorhynchus mykiss)

Ketamine was evaluated as water-soluble anesthetics drug for a species of fish, rainbow trout (Oncorhynchus mykiss). Fish (size ~20 - ~240 gr.) were exposed to a 100-ppm concentration of Ketamine solution (dissolved in water), they were arranged in 4 treatments based on their weight range (Treatment-1= 22.8±3.4 g; Treatment-2= 51.7±4.4 g; Treatment-3= 69.8±5.2 g and Treatment-4= 243.8±20.7 g). Elapsed time for anesthesia duration (stage1 to 3) and recovery duration was recorded. Also, surveillance was evaluated after recovery. Ketamine was effective to cause anesthesia in the fish as 100 ppm concentration. 10 fishes of each treatment (%100) were anesthetized and were induced in stageIII-Plane3 of anesthesia within 2-3 min after exposure to anesthetic solution (Treatment-1= 110.3±3.5 seconds; Treatment-2= 140.0±5.9 sec; Treatment-3= 180.0±5.8 sec and Treatment-4= 190.0±5.8 sec). Anesthesia lasted for 5-6 min while fish were immersed in clean water (water without drug). So, Anesthesia continued for about 5-6 minutes (Treatment-1= 370.3±10 seconds; Treatment-2= 329.6±22 sec; Treatment-3= 300.0±12 sec and Treatment-4= 280.0±5 sec). All fish were alive after recovery. The result shows that Ketamine can produce anesthesia in the fish as a water- soluble drug and it is safe and effective. It may show that Ketamine can be absorbed through gills and can reach the nervous system of fish by blood circulation. The anesthesia duration in every treatment was showed a significant difference compared with other treatments (p<0.05).