Metomidate is an imidazole-based nonbarbituate hypnotic agent that has been used in fish. The drug was initially thought to eliminate the stress response as elevated cortisol peaks were absent in anesthetized patients. This appears not to be the case as it is thought that metomidate suppresses cortisol synthesis through the suppression of 11-B-hydroxylation of cholesterol (Stoskopf 1993d).