The Efficacy of the Aquatic Anaesthetic AQUI-S for Anaesthesia of a Small Freshwater Fish, Melanotaenia Australis

For stage four anaesthesia of the western rainbowfish Melanotaenia australis the most efficacious concentration of AQUI-S was found to be 80 mg l(-1) when five different doses were tested at 27 degrees C (range 26.5-27.5 degrees C). This gave a mean+/-s.e. (n=10) induction time of 140.4+/-8.9 s and recovery time of 180.2+/-8.9 s and resulted in 10% mortality when fish were continuously exposed for 15 min. All fish given this dose during induction and recovery time trials ate within 1 h of recovery, and there was zero mortality during a subsequent 1 month monitoring period.