The aim of this research was to investigate the efficacy of rosewood (Aniba rosaeodora) essential oil (EO) as a new herbal anesthetic compared with camphor (Cinnamomum camphora) EO and commonly used chemical agent 2-phenoxyethanol (2-PE) on goldfish (Carassius auratus). The anesthetic efficacies of these herbal EOs and 2-PE were evaluated in goldfish with mean body weight of 7.36 +/- 0.77 g. Fish were exposed to each anesthetic concentrations and the lowest effective concentrations (LECs) were established according to deep anesthesia (A(D) < 3 min) and full recovery (R-F < 5 min) times. RD and CP showed anesthetic characteristics and induced A(D). The LECs for each anesthetic were established at 250 mu l L-1 for RD (A(D); R-F -> 171 +/- 2.28 s; 297 +/- 7.69 s), 250 mu l L-1 for CP (A(D); R-F -> 129 +/- 4.18 s; 291 +/- 2.81 s) and 700 mu l L-1 for 2-PE (A(D); R-F -> 177 +/- 2.35 s; 214 +/- 4.93 s). At concentrations of 50, 100, 150, 200 mu l L-1 for RD, 50, 100, 150 mu l L-1 for CP and 400, 500 mu l L-1 for 2-PE failed to induce A(D) in goldfish. There were significantly differences found among RD, CP and 2-PE concentrations in terms of induction and recovery times (p < 0.05). The fastest A(D) and R-F were obtained by 300 mu l L-1 CP (120 +/- 1.94 s) and 600 mu l L-1 2-PE (190 +/- 4.34 s), respectively. Fish exposed to 300 mu l L-1 RD and 800 mu l L-1 2-PE took slightly longer to achieve A D than 300 mu l L-1 CP. Induction and recovery times for EOs and 2-PE were significantly dependent on concentrations. Negative relationships was recorded between A(D) and R-F for all anesthetics. No mortality or adverse effects occurred and fish stayed calm during trials. Results showed that RD was found to be an effective anesthetic as well as CP for goldfish and can be used at least 3-fold lower concentrations than 2-PE. In conclusion, rosewood (Aniba rosaeodora) EO, as a new potential anesthetic for fish, proved to be an effective natural agent resulting in rapid induction and recovery.