Anesthetic efficacy of cymbopogon citratus essential oil as a herbal agent in two ornamental fish species

The efficacy of Cymbopogon citratus essential oil (CcEO) as a herbal anesthetic agent was evaluated for two ornamental fish species, Sciaenochromis fryeri and Labidochromis caeruleus. Fish were exposed to various essential oil concentrations and the lowest effective concentrations were determined according to deep anesthesia (AD<3 min) and full recovery (RF<10 min) times. CcEO showed anesthetic traits and induced AD in S. fryeri and L. caeruleus. The lowest effective concentrations was 200 µl/L for S. fryeri (AD; RF → 122 ± 1.8 s; 638 ± 8.9 s) and 200 µl/L for L. caeruleus (AD; RF → 139 ± 6.9 s; 625 ± 11.1 s). At concentration of 25 µl/L C. citratus essential oil did not induce AD in both of ornamental fish species. No significant differences were found between fish species in terms of induction and recovery times for same concentrations excluding AD time of 200 µl/L concentration. Although the fastest AD were obtained by 300 µl/L, recovery times were prolonged and fish did not full recover in 20 min. Induction and recovery times for CcEO were significantly dependent on concentrations and negative relationships were recorded between AD and RF. Neither mortality nor adverse effects were observed on two fish species. As a result, CcEO showed anesthetic properties for S. fryeri and L. caeruleus.